GROWING BLACKBERRIES

A blackberry is a tart, edible fruit produced by a blackberry cane (Rubus species). Blackberry are found worldwide and many species have been selected or crossed and developed into desirable varieties. There are two types, floricane producers that produce fruit the second year of the cane (most common), and primocane producers that produce fruit the first year of the cane.

CHOOSING A VARIETY

SIZE

Blackberries can have two different growth habits, thick stemmed canes that are quite upright, and thinner stemmed canes that are trailing. While all can be managed at about 6 ‘ tall, some need more space on the trellis than others, from 4-7’ depending on variety and management system.

POLLINATION

Most Blackberries are self-fertile, so do not require a different variety as a pollenizer to produce fruit. One exception is Cascade Trailing native to the Pacific Northwest. We do not sell male Cascade Trailing, but Cascade variety, Thornless Loganberry, and Wild Treasure will pollenize Cascade Trailing.

The pollenizers should be planted no further than pollen carrying bees will fly, with no line of sight obstruction, to ensure proper cross-pollination. That distance varies with different bees, 100’ should be a good average distance.

RIPENING TIME

Fruit ripen summer to early fall depending on variety.

USDA HARDINESS ZONE

Blackberry hardiness varies by variety, ranging from USDA zones 4-9. Please see individual variety descriptions This rating tells you the minimum winter temperature the plants typically survive when properly hardened off. We do not have a good rating system at this time for summer patterns (long, short, hot, cool, humid, dry…), but if known, individual descriptions will indicate if a particular plant tolerates (or requires) hot or cool, long or short summers. On our web site you will find a USDA Hardiness Maps (select Growers Information at the bottom of the page) which provides information on the average minimum winter temperature in your location, by zip code.

CHILL HOURS

Many plants native to locations that have cold winters have a Chill Hour requirement to ensure uniform waking up of flower and leaf buds in the spring. The chill hour requirement of plants varies by species, by cultivar, and sometimes by the level of dormancy achieved.

WHERE TO PLANT YOUR TREE

Blackberry need to be planted where they receive at least 8 hours of direct sunlight measured in early summer (late June to early August). Sufficient sun exposure triggers the initiation of new flower buds for the next growing season, without which there will be no fruit. Fruit ripening and flavor development are also benefited by the carbohydrate production stimulated by the sun, as well as it’s heat.

Blackberry tolerate a wide variety of soils so long as they are well drained and moderately rich with a pH around 6.3-6.8. Improve your soil where you intend to plant by mixing an inch or two of plant based organic matter (manures are best for vegetable gardens), peat, or coconut coir into an area 1 1/2 to 2 times the diameter of the needed planting hole and up to a foot deep. A 2-4” deep layer of mulch (straw, leaves, or wood chips) applied after planting will continue to improve the soil.

Allow sufficient space for both the top of the tree and it’s roots when selecting the planting location. Refer to size descriptions for each variety, keeping in mind these are generally managed or pruned sizes, not maximum potential sizes. If you are planting an orchard be sure to include enough space between rows for transporting supplies in and fruit out.

GROWING IN CONTAINERS

To grow a Blackberry in a pot you will need a final container size of at least 20 gallons. Provide a trellis to support trailing types, a single stake will help support upright types. Canes will grow larger in a larger container, but make sure you have the ability and tools to move the pots heavy weight. Or try the new Bushel and Berry Baby Cake variety that grows to only 3’ tall, and can be maintained in a smaller container. It is important for the establishment of the root system to gradually increase the size of the container over several years, rather than go from small directly to very large.

Do not use soil from your garden in the pot, instead use a potting soil mix with some added compost. For larger pots use a potting mix that has larger particles in addition to the smaller.

CARE AND MAINTENANCE

WATERING YOUR TREE

This is the most important and often the most difficult part of successfully growing plants. There are many factors, including the humidity, temperature, soil type, wind, and amount of direct sun that affect how much and how often water should be applied.

A general rule of thumb for plants in the ground is to ensure they receive an inch of water per week over the root zone. An inch of water is equivalent to about ¾ to one gallon per square foot of soil surface area. The typical three foot diameter planting hole would need 7 ½ to 10 gallons of water per week provided by rainfall or by the gardener.

Apply this water once a week, two times per week if soil is fast draining. This will of course depend on your own conditions and the plants you are growing! DO NOT waterlightly each day because this results in a wet surface and dry root zone area. The soil should be moist but not soggy to a depth of about a foot for most growing plants. The top inch or two can feel dry, and the plant still be well watered. The trick is to have the water available where the roots are. In hotter and sunnier areas, a mulch of straw, bark, etc. can greatly ease the burden of summer watering. For plants in containers, water until the soil is saturated and water comes out of the drainage holes. Let the container dry until the soil is dry to the touch 1-2 inches down (more deep with deeper pots) and the container is lighter in weight. A plant that has wilted canbe receiving either too much or too little water.

In rainy areas like the Pacific Northwest most of the plants that we offer will need relatively little supplemental irrigation ONCE THEY ARE WELL ESTABLISHED in the ground and have had a chance to develop a good root system. However even here it is important to make sure plants have regular, deep watering during the first couple of growing seasons, and the first summer is especially critical. In drier areas, or where soils do not retain water well, permanent irrigation is essential. Remember that you don’t want your trees to just survive, but rather to thrive. Make sure they get the water where they need it, starting at the drip line and extending away from the tree up to several feet ( for older trees) where the feeder roots will be. Drip irrigation and soaker hoses can be an efficient way to deliver the water.

FERTILIZATION

For good steady growth and high productivity, your trees need to have adequate amounts of various mineral nutrients. Some people are fortunate and have naturally rich fertile soil.

Use an all-purpose or balanced fertilizer. A couple of inches of well-rotted compost on the root zone can also be an effective fertilizer. A generous leaf or straw mulch around your trees will not only conserve moisture and help in weed control, but also keeps your soil healthy by building up humus, attracting earthworms, and supporting beneficial fungal organisms. This encourages young trees to be strong, healthy and productive. Avoid applying fertilizer after early summer, doing so can encourage lots of soft new growth that is much more likely to be damaged by winter cold. Excessive use of fertilizer can in-crease disease problems on your plants and can even kill them.

As a general guide, if your tree is producing about one foot of new growth or more a year and has healthy looking foliage, it may not need much or any fertilizer.

PESTS AND DISEASES

Find out what insects and diseases are typical in your area. Ask your local co-operative extension professional what the typical insect and disease issues are in your area. Then you can make selections based on resistance or tolerance information available in our catalog, or, make a plan for controlling problems you can expect with the susceptible varieties you prefer to grow. If you see resistance information about a particular disease for one variety but not another of the same kind of fruit, then that variety may be susceptible or might not have been tested so is unknown. The following are some of the more common issues.

SPOTTED WING DROSOPHILA

SYMPTOMS - Eggs are deposited 7-10 days prior to fruit ripening; holes in fruit, spotty molding, larvae in fruit, exuding berry sap, scarring.

CONTROL METHODS - Monitor with traps. Spinosad. Sanitation: In fall, adults feed on over ripe or split fruit (both vegetable and tree fruit) to prepare for winter.

COMMENTS - Contact your local extension office for the most up to date information on spotting wing drosophila.

LEAFHOPPERS

SYMPTOMS - Stippling on leaf surface, small white jumping insects beneath leaves.

CONTROL METHODS - Pyrethrin or rotenone spray as needed. Insecticidal soap or soap/oil mix.

COMMENTS - May also be seen on apple and pear.

MITES

SYMPTOMS - Leaves stippled, very small crawling insects on the underside of leaves. Webbing often also present on underside of leaves or surrounding new shoot tips.

CONTROL METHODS - May develop resistance to Pyrethrin/rotenone spray. Release predatory mites. Insecticidal soap with ultra-light oil.

COMMENTS - Usually not a problem if pesticides are kept to a minimum. Mites thrive during hot dry weather.

CANE BORERS

SYMPTOMS - New shoots wilt and die in spring. Cutting stem open reveals a white grub tunneling in stem.

CONTROL METHODS - Prune out and destroy affected shoots at once.

COMMENTS - On primocane varieties you get some control by cutting canes to ground each fall

BOTRYTIS

SYMPTOMS - Ripening fruit covered with fuzzy gray mold.

CONTROL METHODS - Maximize sunlight and air penetration. Promptly remove diseased fruit. Don’t over water. Avoid wetting ripening fruit

COMMENTS - Common in excessively wet or shady locations, especially with poor air circulation and overcrowded plants with berrries laying on the soil.

VIRAL DISEASE

SYMPTOMS - Leaves may have yellow veins or other discoloration. Fruit crumbly, small or declining yields.

CONTROL METHODS - No cure, start over in a new location with virus free plants.

COMMENTS - Plant only certified virus free stock. Use virus resistant varieties.

ROOT ROT

SYMPTOMS - Roots are rotted and lack fibrous roots. Fruit stems are shortened, any berries remain small and wither. After hot dry periods older leaves may wither or look scorched or bronzed.

CONTROL METHODS - Plant resistant varieties. See Raintree catalog. Plant in new, deep, well-manured fertile soils, do not allow soil to become water-logged. Apply soil fungicides as a last resort.

COMMENTS - Disease organisms can persist in the soil 7+ years, more if strawberries or brambles are present. Rotate fungicides to prevent disease resistance. Plant on mound if your soil is heavy or poorly drained.

DEER

SYMPTOMS - Browsed shortened branches. Leaves are obviously munched on or plants are pulled up.

CONTROL METHODS - Fences or cages at least 8’ tall. Plastic mesh, electric, or woven wire fences.

COMMENTS - At Raintree, an 8’ woven wire deer fence has worked best. Repellents don’t work consistently. and only trained large dogs patrolling the perimeter are effective. Some have had success with the product “Deerchaser.”

BIRD

SYMPTOMS - Fruits disappear or have gaping holes in them. Strawberries, blueberries, cherries and filberts are most susceptible but most fruits suffer occasionally.

CONTROL METHODS - Reflective Bird Scare Tape can work well. Bird netting. Cages.

COMMENTS - Blue Jays start harvesting filberts when ready to pick, and so should you. Nuts dropped by jays are usually empty.

VOLE/MOUSE/RABBIT

SYMPTOMS - Bark eaten in a band from soil level up to 8” and roots eaten too, usually in snowy areas with lots of mulch or tall grass at base of trees.

CONTROL METHODS - Keep mulch 4”-6” away from trunk. Keep grass short and 1’-2’ from trunk. Use vinyl tree guard wrapped around trunk until tree well-established.

COMMENTS - Voles and mice will chew a couple inches above ground and also into the root system. Rabbits will chew up to 8” high, particularly apple trees.

APHID

SYMPTOMS - 1/32 to 1/8” long pear shaped insects that multiply rapidly, espe- cially on the underside of leaves and on stems. Can be pink, green, black or white. Leaves show red blisters or are curled-down and stems turn black with sooty mold.

CONTROL METHODS - Natural predators like lady bugs and parasitic wasps often provide control. Knock aphids off with water spray. Spray with Pyrethrin, Rotenone, Insecticidal Soap, or delayed dormant oil. Control ants if they are also present.

COMMENTS - Trees can tolerate some infestation. Monitor in late spring and summer. Control is more important on new trees. Grow plants that attract predators, i.e. dill or yarrow.

ANT

SYMPTOMS - Numerous ants scurrying up and down the tree trunk; aphids, scale or mealybug present in large numbers, lots of sticky honeydew, perhaps sooty mold.

CONTROL METHODS - Find hill and apply pesticide. Apply Tangle Trap over 2-3” wide band of paper wrapped around trunk. Eliminate other pathways into tree.

COMMENTS - Ants nurture and protect these insects in exchange for their sugary secretions. Insects may be difficult to control until the ants are controlled.

BROWN MARMORATED STINK BUG

SYMPTOMS - Poking-type feeding damage followed by decay on fruits, nuts, berries and leaves. Deformity in the healthy tissue surrounding the dead tissue. Brown spots can show up in stored fruit.

CONTROL METHODS - Monitor with traps, some broad spectrum pesticides may work. Researchers are working on finding effective controls, but no info has been released yet.

COMMENTS - BMSB over winters in groups in dry protected areas, such as houses. If you find them on or in your home use the vacuum, squishing releases their defensive stink. See stopbmsb.org for more info. Feeding begins in spring when the weather warms up and continues until new adults go dormant for winter.

RUST

SYMPTOMS - Lesions on the upper surface of the leaf, or on the fruit or stems, followed by orangish structures on the bottom side of the leaf, or on the fruit or stems, which produce spores.

CONTROL METHODS - Copper fungicide after harvest before fall rains and again in early spring for prevention of some\ rusts. Remove and destroy infected parts of the plant. If possible select resistant varieties. Many varieties have not been studied. Cedar-apple rust is a problem east of the Rockies.

COMMENTS - Rust diseases require an alternate host, removing the host (within 900’ radius), applying fungicides, or removing infected parts may help. Check with your extension office to see what rust diseases in fruiting plants may be common in your area, and their alternate host.

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