Description History & Interesting Facts
Historically, grapes have symbolized abundance and fertility and have been cultivated for millennia for eating fresh, fermenting into wine, or drying to produce sultanas, currants and raisins.
All members of the genus (Vitis) are shrubs, or deciduous vines with large lobed leaves and tendril-bearing shoots which enable them to clamour up any support to a height of 10m or more, with a spread of several metres. Their small, greenish to white flowers are grouped in inflorescences, and when pollinated the flowers develop into fleshy berries of different shapes and colours, depending on the species.
Vitis vinifera
The Middle East is generally described as the native homeland of Vitis vinifera grape vines. There is evidence of domestication dating back 6000 to 8000 years to the Caucasus region (modern Georgia, Armenia and Turkey), making grapes among the earliest cultivated fruits in these regions.
Plants that belong to this genus have medium to large, 3-lobed leaves that are glossy above and slightly hairy underneath, becoming hairless as they mature to full size. In contrast, American grape species like Vitis labrusca tend to have denser, more persistent brown or white woolly hairs on the underside of their leaves. Vitis vinifera gave rise to the overwhelming majority of grape varieties we cultivate today.
Yeast, one of the earliest domesticated microorganisms, occurs naturally on the skins of grapes, leading to the discovery of alcoholic drinks such as wine. The earliest archaeological evidence of wine-making dates from 8000 years ago in Georgia, and the oldest known winery, the Areni-1 winery, was discovered in Armenia and dates back to around 4000 BC.
Click here to see Google Images of the Areni-1 winery
Consumption of raisins was recorded in Egypt and Persia as early as 2000 BC, and ancient Egyptian hieroglyphics record the cultivation of purple grapes by 2400 BC. The Phoenicians and Greeks played a significant role in spreading grape cultivation to Italy, Spain, France, and North Africa around 1000 to 500 BC. The Roman Empire expanded viticulture throughout Europe, with the Roman army, and later monasteries playing key roles in spreading vineyards to regions like the Rhine valley. Vitis vinifera grape vines were introduced into East Asia via India, and to the New World with European settlers.
By the 9th century AC, the city of Shiraz was known to produce some of the finest wines in the Middle East. Thus it has been proposed that ‘Syrah’ red wine is named after Shiraz, a city in Persia where the grape was used to make ‘Shirazi’ wine.
In 2005, a team of archaeologists concluded that Chalcolithic wine jars discovered in Cyprus in the 1930’s dated back to 3500 BC, and ‘Commandaria’, a sweet dessert wine from Cyprus, is the oldest manufactured wine in the world with origins as far back as 2000 BC.
Click here to see Google Images of Chalcolithic wine jars
In the past all Vitis vinifera grapes had seeds, and due to their short shelf life they were mainly processed into raisins. To successfully do this, the seeds had to be removed and this was done tediously by hand by pressing the seeds through the skin. Later devices were designed to assist with this process.
In 1870, William Thompson, owner of a vineyard in California, introduced a very unique grape variety, and the very first seedless grape which he named ‘Thompson's Seedless’. It was introduced into Europe around 1985 where it rapidly grew in popularity, and most raisins are still made from Thompson's Seedless.
Today Vitis vinifera and its hybrids is the primary grape species used for most of the world's wine production, with modern production heavily centred in Europe, the Americas, and China. The Hex River Valley is the oldest grape growing region In South Africa, and remains the largest producer for exports, followed by the Orange River production region.
Vitis labrusca
In North America, numerous species of native grapes belonging to the genus Vitis proliferate in the wild across the continent. They were part of the diet of many Native Americans, but early European colonists considered them to be unsuitable for wine.
In the 19th century, Ephraim Bull of Concord, Massachusetts, cultivated seeds from wild Vitis labrusca vines, also called the ‘fox grape’, to create the ‘Concord’ grape, which would become an important agricultural crop in the United States, as it possesses a distinct "foxy" (musky, sweet) aroma and is used extensively for making juices, jams, and also sweet, fragrant wines.
Today Vitis labrusca is the source of many grape cultivars, including ‘Catawba’. The vines and their hybrids produce large, luscious thick leaves with soft, very hairy, brown or white undersides, and tendrils are produced on every node of the cane to support the vines rampant growth.
When the berries become fully ripe, they separate easily from the berry stem (pedicel), and if the berry is squeezed gently between two fingers the thick skin will slip easily off leaving the pulp intact as a ball. This trait has earned Vitis labrusca and many of its hybrids the name "slip-skin" grapes.
Unlike Vitis vinifera hybrids, Vitis labrusca varieties can better withstand the severe continental conditions of eastern North America with its severely cold winters and hot, humid summers. Therefore Vitis labrusca cultivars are popular to grow in summer rainfall regions of the world where many grapes of Mediterranean origin battle with the moisture and humidity.
Labrusca varieties are also resistant to the root aphid phylloxera, resulting in them being used as grape rootstock all over the world.
Vitis x labruscana
Hybrids between Vitis vinifera (European grape) and Vitis labrusca (American fox grape) are often referred to as Vitis x labruscana, and offer a middle ground, combining the hardiness of V. labrusca with the refined wine-making qualities of V. vinifera.
Grape garden varieties for SA:
There are too many wonderful garden grape varieties to mention them all here, so do your research to find the ones most suitable for your climate and your needs.
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Vitis vinifera ‘Alphonse Lavelle’
Alphonse Lavalle is a seeded, sweet, juicy and crisp variety from Italy with dark blue-black, medium-sized fruit with a thick peel. It ripens late, towards the end of autumn, and is sought after by gardeners who want delicious table grapes that can also be made into wine and juice, or jams and jellies. It is also good to dry for raisins.
This vine is very ornamental in the garden as the colour of the fruit contrasts beautifully with the foliage. It grows well in large pots, and is well suited to espalier.
Alphonso Lavalle is a hardy grape that thrives in the northern-European climate. While hardy, it performs best in sheltered, sunny positions to avoid harsh, freezing wind damage. Because the fruit has a thick skin, it is protected against illness and fungi.
Vitis vinifera ‘Barlinka’
Barlinka originated in Algeria, North Africa and was brought to South Africa in 1910 by Professor A.I. Perold, the first professor of Viticulture and Oenology at Stellenbosch University. It was extensively cultivated in the Hex River Valley, where table grapes have been cultivated for over 100 years.
In the 1970’s Barlinka was developed through hybridization, combining the best traits of several grape varieties. Barlinka grapes are easily recognizable by their attractive red hue, and quickly gained popularity due to their seedless nature, and firm, sweet, and crisp characteristics. Each bite offers a burst of sweetness with a hint of tartness, making them a favourite for eating fresh and for various culinary uses.
The vine is very attractive in the garden as the red fruit contrasts beautifully with the foliage.
Vitis vinifera ‘Crimson Seedless’
Crimson Seedless is the result of five generations of crosses at the U.S. Dept. of Agriculture in Fresno, California, starting in 1926. In very simple terms, it inherited its seedless trait from ‘Thompson Seedless’, and its red colour from ‘Emperor’. The final selection was made in 1983 and today Crimson Seedless is a registered variety of Sun World International, California. It’s become one of the most popular red seedless grape varieties globally and is especially valued for its long shelf life and resistance to splitting during rain.
Crimson Seedless is one of the most widely grown red seedless grapes in South Africa. The grapes are large and bright red with a thick, tough skin, and firm crisp flesh with a sweet-tart flavour. Crimson’s long hang time on the vine means it’s usually one of the last varieties to be harvested. In South Africa its a late-season red variety, with the main harvest time spanning from late January to March, often continuing into early April in specific regions like the Hex River Valley.
Crimson Seedless doubles as an ornamental vine which provides beautiful shade thanks to its generous canopy. It thrives in warm, sunny climates like California, Australia and South Africa.
Vitis vinifera ‘Dan Ben Hannah’
One of the most famous black seeded grape varieties is Dan Ben Hannah, a variety that was produced by Dr Hochberg in Israel, and as a tribute to his wife he named the grapes “Son of Hannah”. Known for its exceptional taste and high-quality fruit production, this variety was selected from a cross between ‘Black Mikveh’ and ‘Alphonse Lavallèe’, and since its release in South Africa in 1973 it has remained very popular with gardeners.
This particular selection has a dark purple to full black colour, and a full-bodied intensely sweet taste with subtle floral undertones. With their large size, sweet flavour, firm, crisp texture and attractive colour, they are well-suited for eating fresh. Dan Ben Hannah is an early black cultivar which depending on the region they are grown in, are harvested from late December until mid-February.
Den Ben Hannah is disease-resistant and an excellent choice for gardeners seeking delicious grapes with minimal effort, and because the vines tend to be more compact, it is well-suited to smaller spaces and pots on balconies and patios.
Vitis vinifera ‘Early Sweet’
Early Sweet is a modern white seedless table grape variety developed in Israel and owned by Grapa Ltd. The first commercial plantings began in 1999, and over time its cultivation has expanded globally. It is a vital early-season grape, with significant production in Egypt, Namibia, South Africa, and Spain. In South Africa it is grown extensively in hot, early-growing regions, like the Orange River Valley. In South Africa Early Sweet is often confused with older varieties like ‘Hanepoot’.
Early Sweet is highly productive and the earliest commercial white seedless variety available, and is harvested from late October to November. The berries are round to oval in shape and a good size. They have a milky green to slightly amber colour skin, sometimes with a blush, and are prized for their high sugar content and their crisp, refreshing flavour and slightly tart after taste, often accompanied by a subtle hint of Muscat flavour. Early Sweet Grapes are popular table grapes, and are good for making juice, jams, and wine.
Vitis vinifera ‘Flame Red Seedless’
Flame Red Seedless table grape is a vibrant, early-season cultivar prized for its large bunches of grapes with a crisp texture, sweet and slightly tart flavour, and striking ruby-red skin, make it perfect for fresh consumption.
Flame Red Seedless is a hybrid of ‘Thompson Seedless’ and ‘Cardinal’ and was developed in California in the 1960’s. It remains a favourite for home gardens, and its long shelf life make it one of the most heavily farmed table grapes.
As an early-season variety, Flame Red Seedless is often the first red grape to hit the market, and in key production areas along the Orange River it is harvested from mid-November to January. The vines are resistant to soil-borne diseases but require a long growing season, and fare poorly in cool, damp zones.
Vitis vinifera Grape ‘Red Globe’
Red Globe is a large-fruited, late-maturing grape variety which was developed from multiple complex crosses in the United States in 1957, by breeders Harold P. Olmo and Albert T. Koyama of the California Agricultural Experiment Station at the University of California, and released as a commercial table grape.
It is one of the largest table grape cultivars, and won the title for the ‘Largest Bunch of Grapes’ featured in the Guinness Book of World Records on August 4th, 2018. It was grown in Spain, and the bunch weighed in at a whopping 10.12kg! This variety has expanded in cultivation worldwide and is grown on almost every continent in home gardens and commercial vineyards.
Red Globe grapes are named for their round appearance and beautiful skin which ripens to varying shades of dark red, red-purple, bright red, and red-pink, depending on growing conditions, and the skin is enveloped in a waxy blue-grey bloom. The grapes are a slip-skin variety, meaning their skin can be easily removed from the flesh.
The translucent pale-green to purple-white flesh is crisp and firm, with a mild, refreshing sweet flavour with subtle fruity nuances. The flesh also encases a few tiny seeds. Red Globe grapes are mostly eaten fresh and in salads and juices, and are also incorporated into a wide array of sweet and savoury culinary preparations. They can also be dried for raisins, and while not as common for wine production, they can still be used in blends.
The vines are easy to grow and highly productive, and in South Africa they are typically harvested during the height of summer, ranging from late December to early February. Some sources indicate the harvest can extend into March in certain regions.
Vitis vinifera ‘Thompson Seedless ’or ‘Sultana’
Thompson Seedless is a versatile white grape of ancient origin, believed to have come from Asia Minor (Ottoman Empire). It’s renowned for its wide range of uses, and is also known as ‘Lade de Coverly’ in the United Kingdom, and oval-fruited ‘Kishmish’ in various parts of the United Arab Emirates and Asia, or just simply ‘Sultana’. In South Africa Sultana is one of the most popular grapes.
The seedless fruit is round and small to medium-sized, with light-green skin that has a golden sheen, and a delicate sweetness that makes them ideal for drying, baking, snacking and adding to fruit salads and desserts. In South Africa they are primarily harvested from late December to February, often peaking between early January and mid-February.
Commercially they are used for winemaking, fruit concentrate, and canning. The leaves of this vine are also edible and often used as wraps for fillings in dishes like ‘dolmas’.
Sultana vines thrive in hot, dry conditions with no humidity, making them ideal for places that experience fairly intense summers. The vine grows vigorously, and will need a strong trellis, and thanks to its bold-textured, deep green foliage and beautiful thin clusters of berries in large, long bunches, is perfect for use as screens on arbours or fences.
Vitis vinifera ‘Hanepoot’
In South Africa ‘Hanepoot’ is the name given to a seeded grape cultivar which is of North African origin. The ancient Egyptians are known to have used it for making wine, earning it the name “Muscat of Alexandria”.
The medium sized, seeded round berries are green and the shape is sometimes a little irregular. The flesh is quite soft and very sweet, offering a delicious Muscat flavour when at its best. Hanepoot is beloved in South Africa as a table grape, and makes an exceptional juice. It is also dried for raisins, or made into sweet, fortified wines.
Hanepoort does well in summer-rainfall areas but does not like humidity. The fruit is ready for harvest from February to March.
‘Red Hanepoot’
Red Hanepoot, with its lovely pink to dark red berries is a colour mutation of the green variety that was discovered in South Africa. Both varieties are clones of Muscat d'Alexandrie, featuring different skin pigments, but offering the same flavour profile and uses.
Vitis labrusca ‘Catawba’
The Black Catawba grape is an American grape variety that produces moderate sized clusters of grapes that are nearly cylindrical and fairly compact, and with a striking dark purple skin. Catawba is likely a hybrid of the native American Vitis labrusca and the Vitis vinifera cultivar ‘Sémillon’. Its exact origins are unclear but it seems to have originated somewhere on the East Coast between the Carolinas and Maryland.
Catawba played an important role in the early history of American winemaking, and during the early to mid-19th century, it was the most widely planted grape variety in the country, and the grape behind Nicholas Longworth's acclaimed Ohio sparkling wines that were distributed as far away as California and Europe.
The fruit has what’s referred to as a “slip-skin grape” as the pulp slips easily out of the skin when ripe if the berries are squeezed between two fingers, leaving the pulp intact. The seedless pulp is described as having a pronounced musky or ‘foxy’ flavour which is still used for winemaking and for juice, jams and jellies.
Catawba was embraced for its hardiness and ability to handle the severe continental climate of the Eastern United States which includes cold winters and hot, humid summers, overcoming the failures of European Vitis vinifera in the eastern US. Despite its cold hardiness, because it is a late ripening variety, in locations with short growing seasons where winter comes early, it is susceptible to harvest time damages.
‘Pink Catawba’
In the 1940’s, French-American Viticulturist Charles Fournier discovered a clonal mutation of Catawba in his Finger Lake vineyards that had less pigmentation in the skin and could produce a lighter rosé wine than the usual Catawba variety. Fournier decided to use this variety, named ‘Pink Catawba’, in his New York sparkling wine from Gold Seal Vineyards. In 1950 this sparkling pink Catawba was the first non-California wine to win a gold medal at the wine tasting competition at the California State Fair.
Grape 'Flame Red Seedless' Uses of Grapes
Whether they are eaten fresh or used in their dried form as raisins, currants and sultanas, grapes hold cultural significance in many parts of the world, and particularly for their role in winemaking. Commercially cultivated grapes are classified as either table or wine grapes.
Table grapes often have large, seedless fruit and thin skins. Wine grapes are smaller and commonly have seeds, and their thicker skin is a desirable characteristic in wine making, as most of the aroma in wine is derived from the skin. Wine grapes also tend to have higher sugar content than table grapes as they are harvested when their juice is approximately 24% sugar by weight. By comparison, commercially produced pure grape juice, made from table grapes, is usually around 15% sugar by weight.
In most of Europe, North America and South Africa any variety of dried grape is referred to as "raisins" A sultana was originally a raisin made from ‘Sultana’ grapes of Turkish origin, also known as ‘Thompson Seedless’. A currant is a dried ‘Zante Black Corinth’ grape, the name being a corruption of the French ‘Raisin de Corinthe’ or ‘Corinth’ grape.
Besides being used extensively in winemaking or for eating fresh, grapes are also enjoyed cooked and can be processed into a multitude of products such as jams, juices, vinegars, and grape seed oil.
Grape 'Thompsons Seedless'Health Benefits
Grapes offer a host of health benefits, and the best news of all is that most of these health benefits are true of fresh grapes, grape juice and most importantly, wine!
Rich in antioxidants like resveratrol, flavonoids and Vitamin C, grapes help combat oxidative stress and inflammation, thereby supporting a healthy immune system and reducing the risk of chronic diseases. They’re also high in fibre aiding in digestion and supporting gut health.
Compounds like polyphenols in grapes contribute to improved heart health by promoting proper blood circulation, reducing blood pressure and enhancing the function of blood vessels.
Despite their sweetness, grapes have a low glycaemic index, making them a suitable option for those managing blood sugar levels.
Including grapes in your diet has also been linked to cognitive benefits, potentially protecting brain health and cognitive function as you age.
An offset to the improved eating quality of seedless grapes is the loss of the potential health benefits provided by the enriched phytochemical content of grape seeds.
Grape archway Image by Steve Buissinne from PixabayIn the Garden
Grapevines have a very long lifespan and can grow for over 120 years, so select the perfect position for your vine in the garden and it will be there for future generations to enjoy. If you have a small garden grapes can be planted in large pots and trained upward.
Grape vines do not have aggressive root systems and need very little space on the ground. If they are pruned carefully, they look luxurious if trained to grow up a wall or over a gazebo, pergola or arch, where the hanging fruit can be admired. You could build your own rectangular frame with wooden poles, making it big enough to place a small table and a few chairs underneath. Train the vines up the structure, and in a couple of years you will have a luscious, shaded canopy to rest under in summer.
Grapevines can also be trained to produce fruit along two horizontal branches (cordons) as espaliers. Cordons are permanent, horizontal, woody arms of a grapevine trained along a trellis wire, usually extending in two directions (bilateral) from the main trunk. They provide a fixed structure from which fruiting canes, or spurs, grow annually and are cut back each winter.
Some varieties are known for their excellent autumn foliage with the leaves turning all kinds of beautiful shades before they drop in winter to allow the winter sunshine in.
Click here to read my article “How to grow fruit trees in small spaces”
Grapevines Image by Conny Griebel from PixabayCultivation
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Ensure that you select the correct varieties for your climate, and those that will best suit your needs.
Seedless grape varieties are sold for fresh consumption and for drying, and while wine grapes are still delicious eaten fresh, they generally have higher acid, higher sugar, higher skin-to-pulp ratio, and more seeds than table and juice grapes. For winemaking you will need to choose the variety more carefully, considering what varieties will make the type of wine you want, and what training and pruning they will need.
Are grapes self-pollinating?
Cultivated Vitis vinifera vines are mostly self-fertile, but cross-pollination increases yields.
The wild species Vitis labrusca usually produces separate male and female plants, but in cultivation, hermaphrodite flowers have been selected.
Grapes are pollinated by wind and insects, with bees providing the best fertilisation and fruit production.
What climate type is perfect for growing grapes?
Grape vines thrive in Mediterranean type climates with mild wet winters and dry summers, and are extensively farmed in the winter rainfall regions of the Cape. However, as long as they are planted in well-draining soil, preferably on the sandy side, they also do well our summer rainfall regions.
South Africa’s premier commercial grape-growing regions are primarily situated in the Western Cape, Northern Cape, and Limpopo provinces.
Are grape vines hardy to cold and frost?
While Vitis vinifera and its hybrids are hardy and need a dormant period in winter, they prefer milder, non-extreme conditions. The vines can experience damage to their trunks and buds at temperatures below -15°C, and hybrids of this species are even less hardy.
On the other hand Vitis labrusca and its hybrids are extremely hardy but temperatures below -20°C can cause injury.
South Africa doesn’t have such extremes, with the coldest temperature of -18.6°C officially recorded at Buffelsfontein near Molteno in the Eastern Cape on June 28, 1996. So, if the correct varieties are planted and the vines are cared for correctly, grapes can flourish virtually throughout the country.
In South Africa many excellent cold-hardy grape varieties are available for gardeners and hobby winemakers. Seeded table grapes are generally more cold-hardy and vigorous than the newer seedless varieties.
The real danger to grape vines is late frosts in spring when the plants are budding or blooming, damaging the harvest. Planting on a slope ensures good drainage and air circulation, and also helps prevent frost.
Winemaking varieties suitable for colder inland regions like the Highveld include: 'Cabernet Sauvignon' and 'Chardonnay', which can withstand cooler and even frost-prone climates if properly managed. 'Pinotage' is another hardy variety, and 'Catawba' is a highly versatile American hybrid, known for its strong tolerance to colder conditions.
Hardy table grape varieties include: 'Barlinka', 'Flame', 'Red Globe', and 'Crimson Seedless'.
Position
Site your vine where it receives 6 to 8 hours of sunshine daily and where it is protected from harsh winds.
What soil type is best for grape vines?
The best soil for grapevines is well-draining, moderately fertile, and slightly acidic to neutral (pH 5.5–6.5). Excessively rich soil leads to excessive vine growth rather than fruit.
Grapevines prefer deep soils to allow for deep root systems. Prior to planting, you can improve soil structure with compost, and adjust pH with lime if necessary.
Sandy loam or gravelly soils are ideal because they provide excellent drainage, warmth, and aeration, which helps prevent root diseases.
Chalk/Limestone soil has good drainage and is ideal for many wine grape varieties.
Slate/Schist: Retains heat well, assisting in ripening, especially in cooler climates.
Planting on a slope ensures good drainage and air circulation.
Add mulch every spring, leaving as large an area as you can free from weeds and other plants around the base of the vine.
Fertilising grape vines
In general, grape vines are not heavy feeders and do not need much fertiliser after they are well-established. Too much fertiliser can stimulate wood and leaf growth rather than fruit production. Moderate amounts of fertiliser during the first and second years after planting will help stimulate young plants to size up for earlier fruit production.
Feed established grape vines in early spring when new growth begins to emerge, and again about a 6 weeks later, but do not fertilise past mid-summer. Feeding too late in the season will promote new, tender growth that is susceptible to damage from an early frost or freeze.
Avoid over feeding grapevines as too much fertiliser damages them easily. If you use an organic fertiliser there won't be the worries about burning your plants.
A good fruit and flower fertiliser like 3:1:5 is fine to feed grapevines with, and specimens growing in pots will need more frequent feeding than those growing in the ground.
How to water grape vines
Young plants will need regular watering but established vines don’t need too much water, and a moderate watering every two weeks should suffice.
Reduce watering during the ripening stage.
Grape vines need a sturdy support system
Grapevines will need some sort of support system to clamber up and it’s best to add this before planting so as not to damage the roots later on. Remember that grape vines are big, vigorous plants, so the support structure needs to be strong enough to bear the weight of the vine.
How to plant a grape vine correctly
Due to their vigorous growth habit grapes are hungry plants, so make sure you prepare their planting holes well, and at least one week before planting time. The holes should be about 60cm deep and wide. Water the plants in their bags a day before planting.
Add a generous amount of compost along with some organic fertiliser and bonemeal to the mounds of topsoil you dug out, mixing it in well. Remove the vine, and if the roots are bound, gently tease the main roots out and spread them out in the planting hole with the roots going downwards at a 45-degree angle, all the way around the hole. Never try to squeeze long roots into a hole that is too small, rather dig a bigger hole.
Grapevines are grafted onto rootstock, and when you buy a grapevine, the join will be clearly visible above the line of the soil in the pot. When you plant out your vine, this should remain above the soil.
Tie the vine to its support, and once it is firmly planted and tied to its stake, mulch well around the base of the plant with more compost and water well.
If you are planting several varieties, space them 3m apart.
For newly planted grapevines, remove any flowers for the first two years. In the following three years, leave only a few bunches of grapes on the vine until it's established, at around five years old.
Growing grape vines in pots
If space is limited, you can train a grapevine as a standard plant. This has a single stem with a head of branches at the top, like a lollipop. It’s ideal for containerised plants and makes an attractive garden feature. However, you will only get a modest crop.
Grape vines need large pots at least 60cm deep and sturdy enough to hold a support. Add your support before planting to avoid damaging the roots. In very hot summer regions, avoid dark colours that trap heat. Wood, like old wine barrels, is an excellent choice.
Potted plants do well if equal parts of potting soil and well-draining cacti and succulent soil are mixed together.
Potted vines will need greater care in terms of watering and feeding. Feed during the growing season with organic 3:15 fertilisers, or a slow-release fertiliser, and top up the soil in the pot once a year in spring.
Grape 'Sun Red Seedless' How to prune grapevines?
If you are growing grapes commercially, and especially if they are going to be mechanically harvested, pruning has to be precise and you could spend days researching various methods. Thankfully, for home grown vines that are harvested by hand pruning is a lot simpler.
Because grapevines are vigorous climbers they respond well to heavy winter pruning, and also need management throughout the growing season to produce a good harvest. If left unattended, grapevines can become unruly, and fruiting will be poor due to overproduction of vegetation.
Whether they are grown for dessert fruit or winemaking, pruning grapevines properly, will lead to better yields and higher quality fruit.
For better-tasting grapes, pick off the smaller clusters in early summer to redirect energy to the stronger bunches. Pinch back any foliage that covers the fruit to make sure it receives sunlight.
The first year
In the first year, the goal of pruning grapevines is to establish a single, strong, straight vertical stem which will become the trunk. This means that if the grapevine you bought has many stems you need to select the strongest one to grow up and cut out all the other branches.
Tie this stem to a sturdy trellis or support and encourage upward growth throughout summer by removing any fruit and all lateral shoots. Lateral shoots grow just above a big leaf on the main stem, and when pinching off the small lateral shoots, be careful to leave the big leaves on the stem to continue feeding the plant.
Once the main shoot (trunk) almost reaches the height of the trellis wire, cut out the growing tip to encourage branching.
Pruning established vines
The main grape pruning season is when the vines are fully dormant in mid-winter. Pruning after mid-winter will lead to sap bleeding. However, in sites prone to spring frosts, you could consider delaying pruning until early spring. The resulting bleeding won’t usually have a significant effect on a healthy vine. However, if you want to make any larger cuts into older wood, do it when the vine is fully dormant.
Ensure that all your pruning tools are sharp and sterilised after each vine is pruned. This helps to prevent fungal infections.
Pruning wounds should be treated against fungal infections by spraying a fungicide solution directly after pruning, and for large cuts, apply a wound sealant. Pruning should never be executed on rainy days, or if rain is expected.
Don't be frightened to prune and cut hard, as grapevines grow strongly and always fruit on new growth.
Pruning Methods for Grape Vines
There are two main pruning methods for grapevines: ‘Cane Pruning’ and ‘Spur Pruning’
Cordon Spur Pruning
With cordon spur pruning, the vine is trained so that two “arms” (or sometimes just one) are trained to grow horizontally from the trunk. These arms are called “cordons” and become a fixed part of the vine.
Click here to see Google Images of grape cordons.
From these arms, new canes grow up vertically in summer each year. The cane houses buds that form shoots, leaves and grape clusters for a single season. In winter when the vines are dormant, select the strongest canes to keep and remove all the others. Try to space the canes about 15cm apart.
Once all the canes are correctly spaced you need to prune the ones you selected to keep by pruning them right down to short spurs containing two to three buds each. It is these buds that push the following year’s canes, and the cycle begins anew.
Click here to see Google Images of Grape Spurs
Click here to see Google Images of Grape Buds
Cane Pruning
A cane is a green summer shoot that has matured and hardened off during summer into a woody, light brown, one-year-old cane. The cane houses buds that form shoots, leaves and grape clusters for a single season.
With cane pruning, there are no permanent cordons (arms). Cane pruning requires manually cutting back nearly all of the vine’s prior growth and selecting new canes to train as cordons that will be responsible for next season’s production.”
Each year, two or more new canes are selected and trained to grow horizontally from the trunk, while the old ones are pruned away. The remaining canes contain numerous buds, and these buds push the new canes and fruit for the season, and then the process is repeated the following year.
This method is commonly used for table grape varieties like Thompson Seedless and Flame Seedless.
If space is limited, you can train a grapevine as a standard plant. This has a single stem with a head of branches at the top, like a lollipop. It’s ideal for containerised plants and makes an attractive garden feature. However, you will only get a modest crop.
Grape 'Dan Ben Hannah'Harvesting & Storing Grapes
Grapes accumulate sugars as they grow on the grapevine through the transportation of sucrose molecules that are produced by photosynthesis from the leaves. During ripening the sucrose molecules are hydrolyzed (separated) into glucose and fructose.
Because grapes won’t continue to ripen after they’ve been harvested, the best way to tell when they are ready is to taste them. The fruit can be left on the vine for several weeks. To harvest, cut using harvesting shears or a sharp knife.
Grapes for eating should be consumed fairly soon after picking, although they will retain flavour for a week or so in a cool storage area, or fridge.
Making raisins to store abundant harvest is easy but time consuming,but can be lots of fun for the whole family to do. Simply pick firm, fresh fruit from the vine, rinse and lay out the bunches on a rack. Then cut of all the thick stems, but don’t trim all the way. Leave in the sun to dry, covered with nets to protect from flies, birds and bees. Three to six days later, you’ll have raisins. It’s almost impossible to over dry, them so don’t worry if you leave them out a bit longer.
Problems, Pests & Diseases of Grapes
The most damaging pests of wine grapes besides birds are grapevine mealy bugs, and snout beetles. Other key pests include phylloxera and nematodes.
Grapes are susceptible to diseases, particularly in humid summer climates. Organic fungicides for controlling powdery and downy mildew on grapes in South Africa include copper-based products like Biogrow Copper Soap and Efekto Virikop, sulfur-based treatments like Kumulus WG, and eco-friendly options such as Margaret Roberts Organic Fungicide.
Grapevine Mealybugs
Grapevine mealybug is a key pest on grapevines in South Africa, particularly as it is the vector of grapevine leafroll virus. Mealybugs suck the plants sap, feeding on the trunks, branches, shoots, leaves, and also the grape bunches. In high numbers this can cause browning and wilting of leaves, desiccation of bunches, and loss of nutrients leading to premature leaf drop. Repeated serious infestations can even result in the death of individual vines.
Grapevine mealybugs can be transmitted by ants and the appearance of ants can indicate a possible mealybug infection since the honeydew they secrete is the primary food source of ants.
Biogrow Neudosan; Biogrow Bioneem; Biogrow Pyrol; Margaret Roberts Organic Insecticide; and Oleum, all work well for mealybugs.
If you suspect mealybugs in the soil, you can drench the soil with systemic products like Kohinor.
Click here to see Google Images of Mealybugs on grape vines
Snout Beetles
Snout beetles attack the buds, leaves, vine shoots and grape bunches and eats holes in the leaves and shoots.
Physically removing and killing the beetles or a sprinkling of insecticidal powder should take care of the mature beetles, provided they have not been there too long. The number of perforations and their distance from the centre of the plant will tell, at a glance, for how long the beetles have been active.
The easiest way to prevent and treat infestations is to drench the soil twice a year, in spring and again in midsummer, with a systemic insecticide like Kohinor, which eradicates sap sucking bugs. The reason systemic insecticides are so effective is that they are taken up by the sap of the plant.
Organic growers can spray with neem as it is a good preventative and contact bio-pesticide for the control of snout beetles and other pests as it is a growth regulator, anti-feedant and general insect repellent to disrupt the normal metabolic activity of insects. Several applications may be required.
Click here to see Google Images of Snout Beetles on grapevines.
Phylloxera
Phylloxera is a small aphid that lives in the soil and feeds on the roots of grapevines, and is especially active during September to May. Digging gently around the roots of weak vines will reveal the yellow insects on the damaged parts of the roots. Under certain conditions, it can also feed on the leaves, showing as galls on the undersides.
Phylloxera occurs more frequently in heavy soils, and un-grafted vines are more susceptible. The most common method of control is to use tolerant rootstocks.
Click here to see Google Images of Phylloxera damage on grapevines.
Nematodes
Nematodes are microscopically small and damage the root systems of grapevines. Some nematodes live inside the root and can cause root knot, while others only attack the roots externally.
Because nematode insecticides are very toxic and should be handled and administered with care and always under supervision, they are only available for commercial growers after analysis of the soil and roots.
For gardeners living in areas prone to nematodes, nematode-tolerant rootstocks should be selected. Certain cover crops like marigolds and oilseed radish (Raphanus sativus subsp. Oleiferus) can be grown around the vines in summer, as they have a suppressive effect on nematode numbers, and in autumn they are pulled up and lightly dug into the topsoil to decompose. They should reseed themselves and pop up again in spring.
Click here to see Google Images of Nematodes on grapevines.
Downy mildew
Downy Mildew thrives in cool, wet conditions, attacking leaves and clusters. Yellowish patches occur on the upper surfaces of leaves, often limited by the veins, corresponding to whitish patches of 'mould' growth on the lower surfaces.
Click here to see Google Images of Downy Mildews on grapevines.
Powdery mildew
In summer, higher temperatures with lower rainfall encourage the development of powdery mildew, showing as a white powdery fungal growth on the leaves, stems and fruit damaged by powdery mildew may split or may drop prematurely. Fruits damaged by powdery mildew are often then infected by the grey mould pathogen and rot, or become mummified.
Click here to see Google Images of Powdery Mildew on grapevines.
Grey mould
Fruit becomes soft and brown, especially as it starts to ripen and a fluffy grey mould may appear on the affected fruits, particularly when humidity is high.
Click here to see Google Images of Grey Mould on grapevines.
Toxicity:
The consumption of grapes and raisins presents a potential health threat to dogs. Their toxicity to dogs can cause the animal to develop acute kidney failure (the sudden development of kidney failure) with anuria (a lack of urine production) and may be fatal.