If you are trying to identify jostaberry from its fruit, take note that the color of the berries changes as the growing season progresses. When they first appear, they are green. They change to red and to purple before maturing to the color they attain when they are ripe: violet-black. An identifying feature that remains more constant is leaf appearance. A jostaberry leaf is green, has prominent veins, bears teeth along its edges, and is divided into irregular lobes. Among other features, jostaberry is valued for its fast-growing quality and for its ability to bear fruit in relatively cold climates. Learn how to grow and care for this unusual fruiting shrub.
Selecting a Site
Choose a full sun location with good drainage for your jostaberry bush. If the site does not already have good drainage, improve soil drainage by mixing in organic matter.
Spacing
Plant jostaberry bushes 6 feet apart from one another. This gives each bush enough room to reach its maximum size without casting shade on the plant next to it. Adequate spacing also helps cut down on infestations of certain plant diseases and insect pests. To install the plant in the ground, follow the same rules you would for transplanting any shrub, including the rule that the width of the planting hole should be twice that of the root ball.
Jostaberry Care
Light
Jostaberry bush will yield an optimal harvest if grown in full sun. In the North, it will tolerate partial shade, but will not perform as well. At the southern end of its growing range (zone 7), it will profit from some afternoon shade.
Soil
Jostaberry bush prefers a well-drained soil that with lots of decomposed organic matter mixed into it. However, it will tolerate a soil on the sandy side as long as you water well.
Water
This plant requires an average amount of water. However, take into account the soil type where it is growing. Water drains through sandy soil more quickly, requiring more frequent watering.
Temperature and Humidity
One of the strengths of jostaberry is its relative hardiness (to USDA zone 4) for a fruiting bush. It can survive temperatures to as low as -40 degrees F but also holds up well to summer temperatures in the median zones. It does requires a chilling period of 1000 hours in order to produce fruit. This make fruit production a little more sketchy when grown in the heat and humidity of the South (below zone 7).
Fertilizer
Fertilize with compost every spring. In addition, use a mulch such as straw which, along with suppressing weeds, helps retain soil moisture and releases nutrients as it decomposes.
Types of Jostaberry
There are different cultivars of jostaberry. Distributors don’t always distinguish between them, selling them generically as jostaberry bushes. In some cases, a particular cultivar represents a cosmetic difference rather than a practical improvement. If you can find them, cultivars include:
‘Josta’: the original cultivar and the one most commonly available’Red Josta’: fruit has more of a reddish tinge than it does on the original’Jostine’: bears larger berries than the original does’Jostaki’ (also called ‘Jogranda’ or ‘Jostagranda’): bears even larger berries than ‘Jostine’‘Orus 8’: may represent the most improvement over the original, with superior-tasting fruit and extra resistance to diseases
Harvesting Jostaberries
Jostaberry takes 2 to 3 years to bear fruit. Harvest when berries have turned bluish-black and are firm to the touch. The time of year when this happens varies according to climate. In some areas, you can harvest in July. In others, you need to wait until later in the summer. Under the right conditions and with the right care, jostaberry bushes will bear fruit for ten to fifteen years. The berries can be frozen after harvesting. Jostaberry is self-pollinating, so you do not have to grow more than one. However, growing multiple plants may increase pollination and result in larger harvests.
Pruning
Pruning is an important part of jostaberry care. The fruit grows only on canes that are at least one year old. After a few years, canes get old and productivity declines. So each winter, prune out the oldest canes, along with any dead, diseased, or damaged canes. Such pruning keeps the plant vigorous by releasing more energy into generating new canes.
Propagating Jostaberry Bushes
Before propagating a plant, make sure it is legal to do so. When in doubt, acquire new plants through nurseries. Cultivars tend to be patented. For example, the ‘Jostaki’ cultivar of jostaberry is patented. If you grow a currant, gooseberry, or jostaberry and wish to have more, it is possible to propagate your plant in either of two ways, and you can undertake both operations in spring: by cuttings or by offshoots. Here’s how:
Cuttings
Take a cutting any time of year except summer which can stress the plant. You need bypass pruners, a container, potting mix, a pencil, a shovel, and rooting hormone. Follow these intructions:
Offshoots
You can also propagate via an offshoot, a method that requires just two supplies: pruners and a shovel. Here’s how:
Overwintering
Jostaberry is cold-hardy to zone 4. If you feel that you are in a borderline zone and wish to insulate your bush against freezing temperatures, apply a 3 inch layer of mulch around the base. Avoid piling up mulch against the trunk, which invites diseases and pest damage.
Common Pests and Plant Diseases
Jostaberry bush is relatively resistant to diseases. This is especially true of the cultivar, ‘Orus 8.’ Your main challenge will be keeping wild birds from eating the berries before you can harves. Cover the shrubs with netting to keep birds and other pests from stealing your harvest. There are also the usual, smaller pests to be on guard against. Pests that attack the plant’s foliage include slugs, snails, and aphids. Slugs and snails can be controlled by setting traps for them. Aphids are best controlled by spraying them with organic Neem oil as soon as you detect their presence on the undersides of leaves.
