How to Grow and Care for Red Currant Bush

Red currant bushes are fast-growing, hardy shrubs that produce tender, tart red berries in late June to mid-July, usually after their second year. With their upright growth habit and attractive, maple-like leaves, red currant bushes are an excellent addition anywhere in your landscape. The plants are self-fertile, meaning you only need one plant to produce berries.

How to Plant Red Currants

When to Plant

Plant bare-root plants purchased from nurseries early in the spring before they leaf out. These plants can also be planted in the fall to establish roots before winter dormancy.

Selecting a Planting Site

Currants prefer a cool, moist growing location and can handle full sun or partial or sheltered shade. These shrubs do not tolerate soggy, waterlogged soil or cramped growing conditions. Allow for good airflow around the plant. If rainfall is insufficient, keep new plants well-watered with one to two inches of water per week during the first growing season.

Spacing, Depth, and Support

Plant 3 to 5 feet apart. If planting in rows, give at least 8 feet between rows. Plant nursery plants an inch deeper than their pot, in holes deeper and wider than their root systems. These shrubs can grow with or without a trellis; however, trellising improves air circulation and lowers the risk of fungal issues.

Warning

Red currants are members of the Ribes genus, banned in some states. In the early 1900s, the growth and sale of these plants were prohibited in the United States due to white pine blister rust, a fungus that needs two hosts to spread, and certain Ribes species are particularly susceptible. Red currants were included in the ban, even though most are resistant to the disease. The ban has been lifted in most states; if your state prohibits red currants, you cannot have the plants shipped to you from a nursery in another state.

Red Currant Care

Established shrubs do not require much maintenance; they are tough and forgiving, but be careful not to damage the shallow roots when weeding.

Light

Red currants need full sun for at least half of the day. In warmer climates, they do best with full sun in the morning and partial shade in the afternoon, as intense sunlight can burn the leaves.

Soil

The soil must have good water-holding capacity and be well-drained with good aeration. Silt or clay loam with a high amount of organic matter is ideal. Sandy soil heats up too much in hot weather. To counter this, amend the soil with organic matter and keep it moist with 2 to 3 inches of mulch.

The ideal soil pH range is 6.2 to 6.5, but red currants can be grown in a wider neutral to acidic pH range.

Water

Established plants only need regular watering up to the point of harvest, after which their active growth stops, and they only need additional water during periods of extended drought. Deep drip irrigation works best for their shallow roots.

Temperature and Humidity

Red currants are winter-hardy; however, their bloom in the early spring makes them susceptible to late frosts. They don’t do well in temperatures above 85°F.

The combination of a warm, humid climate with poor air circulation makes them especially susceptible to powdery mildew.

Fertilizer

Red currants are heavy nitrogen feeders. Fertilize the plants in the early spring with one-quarter to one-third pound of complete fertilizer in a circle around each plant. Also, give the plants an extra nitrogen boost by scattering composted manure around the plants.

Pollination

Red currants are self-fruiting. However,all cultivars produce more fruit with insect cross-pollination.

Types of Red Currants

• 'Red Lake' is a popular cultivar with large, flavorful, juicy berries. It is susceptible to mildew and does not tolerate late spring frosts.
• 'Jonkheer van Tets' is a Dutch variety, an early bloomer that produces prolific fruits, susceptible to late frosts; mildew resistant.
  
• 'Stanza' is a shrub with medium-sized fruit and a compact habit; crop yield comes in mid to late season.
• Ribes rubrum ' White Grape' is also called white currant, ripens in midsummer, and is sweeter than red currants. The berries are creamy white; consider training it against a wall or fence.
  
• 'Rovada,' the preferred cultivar of commercial growers, is a heavy producer of large berries. While it is highly resistant to powdery mildew, it is prone to cane blight.

Red Currants vs. Black Currants

Red currants and black currants are different species in the same gooseberry family. Black currants are Ribes nigrum and are sweeter than red currants, which tend to be more tart. Red currants produce berries on old wood, while black currants fruit on new growth. Black currant shrubs produce white blooms, while red currant flowers have more of a yellowish tint.

Harvesting

Red currants turn red when ripe. The longer the berries remain on the plant, the sweeter and more flavorful the berries (don’t wait too long, though, as wildlife love the berries too). Because the skin of the berries is very tender and rips easily, to prevent a juicy mess, don’t harvest individual berries. Instead, cut off the whole berry clusters simultaneously with bypass pruners or scissors. Wash, dry, then store berries in a breathable container and keep them in a cool, dry place or the refrigerator, where they will stay fresh for a few days.

Harvesting Tip

After harvesting clusters, gently "comb" a regular dinner fork through the bush to retrieve individual berries.

How to Grow Red Currants in Pots

Red currant plants do not mind growing in tight spaces like pots. Plant currants in pots 12 to 18 inches wide and deep. Currant roots do not grow deep. These plants prefer organic potting mix, all-purpose fertilizer, and evenly moist soil. Get pots with ample drainage holes.

Pruning

Red currants produce most berries on 2- and 3-year-old canes, and pruning follows that pattern. The goal is to have eight fruit-producing canes of different ages on the plant.

Prune during dormancy and permanently remove all diseased, broken, or misshapen canes. Remove all except six to eight strongest canes in the first winter after planting. In the second year, do the same with the new growth and also remove all but four to five of the strongest shoots from year one. Repeat this in year three. By the end of the third year, you will have three or four canes for each year of the plant. Remove all old canes that do not bear fruit any longer. They are easy to identify by their dark color.

If you remove canes in error, don’t worry, the plant will bounce back with plenty of new shoots next year.

Propagating Red Currant Plants

At the end of winter or early spring, before the active growth phase, you can propagate red currants from an existing healthy plant by tip layering or stem cutting, producing the same plant as the parent. You can also grow red currants from seed.

Here's how to propagate by tip layering:

1. Place the tip of a cane in the soil and cover it with an inch of soil, then secure it with a rock or a brick.
2. In a year, sometimes sooner, it will develop roots, and you can separate it from the mother plant and transplant it.

Here's how to propagate using stem cuttings:

1. Take a 9- to 11-inch length of the stem from the previous year's growth just above where it meets the older wood. Ensure a bud (or growth node) is at the top.
2. Keep three to four buds at the top, but scrape off the rest along the stem using a sharp knife if there are more.
3. Using the same knife, scrape the bottom of the stem to remove the bark and expose the green layer to help with root formation.
4. Plant half of the stem in the center of a pot with moistened, enriched, well-draining soil. Place the cutting in a cold frame or wintering spot, keep the temperature above freezing, and water. By fall, new growth should be sufficient to plant the cutting in the ground, if desired.

How to Grow Red Currants From Seed

Seeds can be sown in a sandy compost or peat moss but require cold stratification or a cool period before germinating. In the wild, seeds germinate in the spring. Consider putting the seeds in a bag of peat moss, leaving it in a cool spot, and keeping it moist.

1. Poke holes in the bag to allow air circulation during stratification.
2. Put the bag in the refrigerator, above freezing, for three to four months. If temperatures drop below freezing, it can damage the seeds and prevent germination.
3. After the cold cycle, plant the seeds in sand, peat moss, or a soilless seed starting mix.
4. The seeds should be gently pressed into the surface of the mix, thinly layered with a smattering of the mix.
5. Germination occurs best between 65°F to 75°F in bright, indirect light. No artificial heat is needed for germination.
   

Potting and Repotting

Repot currants every three years after harvesting in a pot that is one size up. Refresh the soil and trim the roots to avoid plants getting rootbound.

Overwintering

Red currants are winter hardy; however, early bloomers are susceptible to bloom dieback with late frosts. Protect new spring foliage, buds, and flowers with a floating row cover from late frost.

Common Pests & Plant Diseases

Red currants are most commonly affected by powdery mildew, currant aphids, and leaf spot, which cause leaf damage and defoliation. Cane blight is a severe fungus that leads to the wilting and death of canes. The best way to prevent powdery mildew is to plant resistant varieties. Proper pruning and spacing between plants also reduce the risk of powdery mildew.

From: thespruce