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Plant Manual for Prime-Ark® 45 Primocane Blackberry

To the left, you'll find all the topics covered in this Plant Manual. Select a topic to read its information.

Plant Description

Early and heavy producer. Erect canes make it easy to pick these firm, midnight-black berries. Fruit stores well for longer-term enjoyment. Plants are disease-resistant and cold-hardy. First-year canes begin ripening in mid-July, while second-year canes bear heaviest crops in June. Both continue to fruit until frost. Self-pollinating. May be covered by U.S.P.P. #22449 or other patents. APF-45 cultivar.

Acclimate

Plants grown in a greenhouse must be acclimated carefully before planting or placing them outdoors. This is especially true in hot or sunny locations. Many species should never be grown in full sun. Before purchasing a plant, learn about its sun requirements. Knowing the plants requirements can avoid any damage to the plant by incorrectly giving it the wrong conditions.

If your plant has been grown in a greenhouse, here are a few steps we recommend you follow:

  • After purchasing your plant, place it outside in a sheltered, shady spot or on your back porch.
  • Leave it there for 3-4 hours and gradually increase the time spent outside by 1-2 hours per day.
  • Bring the plants back indoors each night.
  • Water it regularly to keep the plant moist.
  • Occasionally spray the leaves with water.
  • After 2-3 days, move the plants from their shady spot into morning sun, returning them to the shade in the afternoon.
  • After 7 days, the plants should be able to handle the outdoor temperatures, if they stay around 50 degrees F.
  • After 7-10 days, your plant is ready to be planted in its permanent location. Try to do this on a cloudy day and be sure to water the plant well.
  • Observe foliage daily. If any type of leaf discoloration occurs, put the plant back into filtered light and attempt this step at a later date.
  • Special care must be taken to avoid burning the leaves.

These are general guide recommendations. Some plants take longer than others to acclimate.

Location

The best way to succeed is to plan before you plant. Let’s discuss location: Do you know where you want to plant your new berry plant? Avoid many future problems by considering all aspects of the planting spot, such as:

  • Cross-pollination
  • Sun and good soil
  • Leave space for future planting

Cross-Pollination

Is a pollinator variety present? Cross-pollination by a different variety, of the same type of plant, is key to the success of many plants. In most cases, its absence is why the plant doesn’t bear fruit or produces poorly. Most berry plants are self-pollinating, but for a larger fruit and crop plant more than one variety.

Sun and Good Soil

Your plant would love a sunny place with well-drained, fertile soil. But it will be quite satisfied with six to eight hours of sunlight. Good drainage is required to keep your plant “happy.” If your soil has high clay content, use our Coco-Fiber Potting Medium or add one-third peat to the soil at planting time. We do not recommend planting berries in heavy, pure clay soils.

Even if your yard isn’t the most ideal location, take heart. Most berries are very adaptable and respond well to fertilizers, so they can get along well even where the soil is nutritionally poor. Just steer clear of sites with extremely heavy soils or very poor drainage.

Space for Future Plantings

Once you’ve found out about fruit growing goodness firsthand, you’ll want to expand your home orchard. It’s important to plan so that the future growth areas will be ready when you are.

Planting

Few things are as delicious as homegrown blackberries, and the success of your harvest begins right with the planting site and method. For maximum growth and yields later on, give your brambles the best foundation possible.

Before Planting

Before you plant, check your soil pH. This can be done by contacting your local County Extension Office for information about soil testing in your area, or purchase one of our digital meters for quick and accurate results. Ideally, your blackberries need a soil pH between 5.8-6.8. Steer clear of soils that are extremely heavy or very poorly drained.

Spacing

  • Stark Bro’s sells two types of blackberries: erect and semi-erect. Space both erect and semi-erect brambles 3’ apart in the row, with 8’ between each row.
  • Do not plant Red, Gold or Purple raspberries and blackberries closer than 75-100 feet to Black raspberries. Black raspberries are susceptible to viral diseases carried by aphids from nearby plants.

Planting Tips

  • As you plant your new berry bushes, avoid getting them too deep. The crown should be right at soil level, with the roots just under the surface.
  • If your berries are potted, plant them at the same depth they are in the pot.
  • Fill the hole with moist topsoil, then tamp the soil with hands to remove air pockets.
  • Water the plant.
  • Prune back the stems to about 2”. Pruning is not necessary on potted berries.

Additional Notes

  • Do not put fertilizer in hole with plants. We recommend Stark Bro’s® Blackberry & Bramble fertilizer after plants start to green up and start growing. Fertilize lightly the first time and do not put fertilizer directly on plants.
  • Your brambles will live 10-12 years with proper maintenance.
  • For a family of 5, we suggest planting 15-20 plants (3-4 plants per person).

Soil Preparation

Preparing your soil before you plant will greatly improve your plant’s performance and promote healthy, vigorous growth. It is a good idea to have your soil tested to determine if it is lacking in any essential minerals and nutrients. This can be done through your County Extension Office or with one of our digital meters.

The goal of soil preparation is to replenish vital minerals and nutrients, as well as break up and loosen any compacted soil.

When To Prepare Your Soil

Soil preparation can be done at any time that the ground is not too wet or frozen. Your trees may be planted even when temperatures are quite cool. If a hard frost is expected, it is advisable to delay planting for a while until temperatures become more moderate. Generally, as long as your soil is workable, it is fine to plant.

How To Prepare Your Soil

  • Roots grow faster when they’re spread out. Dig the hole deep and wide enough so the root system has plenty of room to easily expand. Keep the topsoil in a separate pile so you can put it in the bottom of the hole, where it’ll do the most good.
  • To loosen the soil, mix dehydrated cow manure, garden compost or peat moss (up to 1/3 concentration) into your pile of topsoil. Make sure the peat moss you get is either baled sphagnum or granular peat. You can also add our Coco-Fiber Potting Medium or 2 or more inches of organic material and work in evenly with the existing soil.

Your lawn can provide you with ideal organic materials such as grass clippings and shredded leaves. Not only will the grass and leaves break down to provide soil nutrients, but they will help loosen the soil as well. You can gather these in the fall with spring planting in mind.

Common soil amendments:

  • compost
  • sand
  • manure
  • lime
  • peat moss

Adding organic materials, such as our Coco-Fiber Potting Medium and compost will improve most every soil type. Organic materials bind sandy soil particles so they retain moisture and nutrients better. They also break apart clay and silt particles, so that water can infiltrate and roots can spread.

Soil Types

  • Clay and silt soils are made of very small particles. They feel slick and sticky when wet. Clay and silt hold moisture well, but resist water infiltration, especially when they are dry. Often puddles form on clay or silt soils, and they easily become compacted.
  • Loam soil is a mix of sand, silt or clay, and organic matter. Loam soils are loose and look rich. When squeezed in your fist, moist loam will form a ball, which crumbles when poked with a finger. Loam soils normally absorb water and store moisture well. Loam soils can be sandy or clay based, and will vary in moisture absorption and retention accordingly.
  • Sandy soils contain large particles that are visible to the unaided eye, and are usually light in color. Sand feels coarse when wet or dry, and will not form a ball when squeezed in your fist. Sandy soils stay loose and allow moisture to penetrate easily, but do not retain it for long-term use.

Fertilizing

Fertilizing is an excellent way to replenish the natural nutrients in your plant’s soil. We recommend using Stark® Bro’s Blackberry and Bramble Fertilizer, which is specifically formulated for blackberries and brambles.

Fertilizing Tips

  • Fertilizer should be applied each spring when new growth starts, and again just after harvest.
  • Fertilize lightly the first time.
  • Do not put fertilizer directly on the plants.
  • Spring cultivation and summer mulching is very beneficial.

Insects and Diseases

Every plant has the future potential for disease and insect damage. Factors such as location and weather will play a part in which issues your plants encounters. If available, disease-resistant varieties are the best option for easy care; and for all types of plants, proper maintenance (such as watering, pruning, spraying, weeding, and cleanup) can help keep most insects and diseases at bay.

Crown Gall

Plants appear stunted and slow growing; leaves may be reduced in size, little or no fruit. If plant is dead, inspect roots for hard, woody tumors. Note: many things can cause stunted plants.

Control

  • Consult County Extension Agent

Aphids

They are the size of a pinhead and vary in color depending on the species. Cluster on stems and under leaves, sucking plant juices. Leaves then curl, thicken, yellow and die. Produce large amounts of a liquid waste called “honeydew”. Aphid sticky residue becomes a growth media for sooty mold.

Natural Control

  • Bonide® Citrus, Fruit & Nut Orchard Spray

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Cane Borer

Adult is a long-horned beetle. Larvae indicated by sawdust.

Natural Control

  • Remove and destroy infected canes.

Other Control Options

  • Consult County Extension Agent

Cane Blight

Enters through wounds made by insects or mechanically. Cause large brown dead areas (cankers). Often first noticed when leaves wilt and wither. Cut back to below cankers; disinfect shears between cuts with 1 part bleach and 10 parts water. Dispose of pruning.

Natural Control

  • Bonide® Citrus, Fruit & Nut Orchard Spray

Chemical Control

  • Hi-Yield® Lime Sulfur Spray

Spot Anthracnose

It is most common on Black raspberry. Reddish-brown sunken spots with purple margins and light gray centers appear on young shoots. Grow together into cankers. Leaves may drop early. Fruit may dry up. Over winters in lesions on old canes. Proper pruning can help control. Always remove and burn old fruiting canes after harvest.

Natural Control

  • Serenade® Garden Disease Control

Chemical Control

  • Hi-Yield® Lime Sulfur Spray

Orange Rust

Not common on Red raspberry but serious on all others, especially Blackberries. Underside of leaves covered with orange-yellow spores. Remove infected plants.

Natural Control

  • Serenade® Garden Disease Control
  • Bonide® Citrus, Fruit & Nut Orchard Spray

Chemical Control

  • Hi-Yield® Lime Sulfur Spray

Fruit Rot

Appears as gray, hairy mold on decays blossoms, green and ripening fruits and harvested fruits.

Control

  • Contact County Extension Agent

Powdery Mildew

Whitish-gray powdery mold or felt like patches on buds, young leaves and twigs. Leaves may crinkle and curl upward. Over winters in fallen leaves.

Natural Control

  • Clean up fallen leaves and other debris.
  • Serenade® Garden Disease Spray
  • Bonide® Citrus, Fruit & Nut Orchard Spray

Chemical Control

  • Hi-Yield® Lime Sulfur Spray

Fruitworm (Sawfly)

Adult is yellow to brown sawfly beetle, 1/4” long. Larvae are brown and white, 1/8” long. Adults make slits in flower buds and larvae feed on berries.

Natural Control

  • Bonide® Captain Jack’s™ Deadbug Brew

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Mites

Pinpoint size, many different colors. Found on undersides of leaves. Severe infestations have some silken webbing. Sap feeding causes bronzing of leaves.

Natural Control

  • Bonide® Citrus, Fruit & Nut Orchard Spray

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Japanese Beetle

Adult is metallic green beetle, which skeletonizes leaves. Larvae are a grub, which feeds on turf roots. Check turf product labels for timing of control of grubs. This is more of this problem is east of the Mississippi River.

Natural Control

  • Traps

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Leafroller

Pale yellow or ‘dirty’ green worms. Leaves are rolled and webbed together where insects feed. Eventually becomes skeletonized.

Natural Control

  • Bonide® Captain Jack’s™ Deadbug Brew
  • Bonide® Thuricide® Bacillus Thuringiensis (BT)

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Rose Chafer

Beetle has 1/2” long, tan wings with reddish-brown edges. Long, thin hairy legs. Skeletonizes leaves and flowers. Present in large quantities in June and July. Worst on sandy sites near grassy areas.

Chemical Control

  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Thrips

Tiny, slender, fringed wing insects ranging from 1/25 to 1/8” long. Nymphs are pale yellow and highly active and adults are usually black or yellow-brown, but may have red, black or white markings. Feed on large variety of plants by puncturing them and sucking up the contents.

Natural Control

  • Bonide® Citrus, Fruit & Nut Orchard Spray
  • Bonide® Captain Jack’s™ Deadbug Brew

Leaf Curl

Leaves thicken and curl much like they have aphids. Spread by insects usually from June until plants ready to cultivate. This is caused by a virus and spread partially by Raspberry Aphid, which are hard to control.

Natural Control

  • Remove and burn dead canes and remove wild berries from the area.

Other Control Options

  • Consult County Extension Agent

Mosiac

Leaves will thicken and curl, display ‘mottled’ color. There will be dark green areas and bright green areas on same leaf. Caused by a virus and spread partially by Raspberry Aphid which are hard to control.

Natural Control

  • Remove and burn dead canes and remove wild berries from the area.

Other Control Options

  • Consult County Extension Agent

Pruning

Pruning is an important part of proper edible plant care, but many people find the task overwhelming. It doesn’t have to be! Keep these things in mind:

  • You can have confidence in knowing that not everyone will prune the exact same way (even the experts).
  • It is best for your plant to do some pruning versus no pruning.
  • There are several reasons to prune: to maintain the size and shape of the plant, stimulate strong growth, and overall fruit quality.

Pruning Tips

Pruning may vary depending on the variety you plant. Some pruning should be done every spring to keep the plants from becoming tangled and to improve their ability to bear. You may want to stake or trellis-train your berry plants to keep them more compact and upright.

Because you get a harvest the first fall on your primocanes, you can also employ the technique of “mowing” your plants down. In late winter, prune all the canes down to the crown. New shoots will grow. When using the mowing method of pruning you can push up the yield time of your blackberries and raspberries by covering them with plastic. This will create a warmer microclimate around the crown of the plant and will promote earlier primocane growth. Remove the plastic after the average last day of frost in your region.

  • For a more bountiful harvest: once these primocanes have grown 3 feet, tip prune your primocanes. This can be done around late June or early July. Cut 6-12 inches off the tip and then give them support. This will encourage branching, thus producing more berries.
  • Do not prune if you want earlier harvests or if flowers have already formed on the tip. Tip pruning will delay fruiting significantly.

Pruning for Multiple Harvests

Blackberries and raspberries are biennial. That means that the cane only grows for two years then dies. The next year’s canes are called floricanes; they will bear fruit in the summer, then die.

For multiple harvests, don’t prune all the canes to the crown. Just prune out the dead or diseased canes to the crown and leave all other canes. This can be done at any time throughout the growing season. Tip prune the primocanes at the right time. The floricanes that you allow to grow from the previous year will bear fruit in the summer, and your primocanes will bear fruit in the early fall through the first frost. This gives you an extended harvest! Once the floricanes have borne fruit, you’ll need to prune them all the way to the crown of the plant.

Additional Notes

  • When pruning in late winter, top dress with compost to feed your plants throughout the growing season.
  • A good reference book, such as our Pruning Made Easy, can answer questions and guide you through the pruning process.

Spraying

Spraying is important to the survival of your plants. To handle potential diseases and pests, reference the guidelines below to know what you should spray, and when you should use it.

Before you begin, read and follow all instructions on labels.

Natural Control

  • Serenade® Garden Disease Control for anthracnose, powdery mildew, rust and more.

When To Spray

Dormancy (late winter/early spring before bud break)

  • Hi-Yield® Lime Sulfur Spray for cane blight.

During New Growth

  • Hi-Yield® Lime Sulfur Spray for anthracnose, powdery mildew and rust.

At the First Sign of:

  • Bonide® Captain Jack’s™ Deadbug Brew for fruitworms, thrips, leafrollers and more.
  • Bonide® Citrus, Fruit & Nut Orchard Spray for aphids, mites, blight, thrips, powdery mildew, rust and more.
  • Bonide® Thuricide® Bacillus Thuringiensis (BT) for omnivorus leafroller.
  • GardenTech® Sevin® Concentrate Bug Killer for aphids, fruitworms, Japanese beetles, mites, rose chafer, leafrollers and more.
  • Bayer Advanced™ Complete Insect Killer for aphids, mites, leafrollers, fruitworms, Japanese beetles, rose chafer and more.

Watering

Unless you’re in an area where irrigation is usually needed for normal plant growth, you probably won’t need to water after the first growing year. Until then, follow these guidelines to get your new berry plants off to a great start.

General Guidelines

  • If summer brings about an inch of rainfall every 10 days or so, you won’t need to use the hose. But if it gets really dry, you can give your new plant a good, thorough soaking. The best way to do this is to let your garden hose trickle slowly. This gives the water a chance to soak in instead of running off. You can also use a soaker hose to water several plants at once.
  • It’s important to note that even if you’re in the midst of a brown-lawn drought, you don’t want to water too much. Once every 10 days or two weeks is plenty. Worse than dry, thirsty roots is waterlogged, drowning roots.
  • Although blackberries are drought tolerant, they do need considerable water during fruiting.

Harvesting

Are you ready to enjoy delicious homegrown fruit? Harvest is the time to enjoy the results of your hard work. Keep a few things in consideration as you reap the fruits of your labor: the best time to pick the fruit, and how to store your harvest.

When to Harvest

You can expect your first crop in the 2nd season. For the best flavor and texture harvest your blackberries when it is dry and cool. The berry should look plump and have a dark coloring. Grasp the berry gently and twist, if the fruit releases easily then it is ripe. While picking berries try to keep them in the shade and don’t stack them more than a couple inches deep in your containers, otherwise you will squash your berries.

It is best to harvest every 2 or 3 days, to avoid over ripening or rotting fruit. Blackberries do not keep long after picking, at most 4 or 5 days in the refrigerator.

Annual average yield per plant is around 1 quart.

Storage

Refrigerate your berries immediately after harvesting. Do not wash berries until you are ready to use them. Washing makes them more prone to spoiling.

If not able to use right away put berries on a cookie sheet in a single layer and freeze until firm and then put them in freezer bags to enjoy all year long.


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Bare-root Trees

Trees that are shipped without soil to ensure good contact with soil in your yard. When shipped, they are about 3-4' tall with 3/8" or larger trunk diameter. When they mature, they will be one of three sizes*:

Dwarf

Matures to be about 8-10' tall and wide. Provides an abundance of full-size fruit.

Semi-Dwarf

Matures to be about 12-15' tall and wide. Gives maximum fruit yield per square foot.

Standard

Matures to be about 15-25' tall and 20' wide. A multi-purpose fruit and shade tree.

Stark Supreme Tree®

Top-grade, bare-root trees that give you a head start on growing. When shipped, they are about 4-5' tall with 5/8" or larger trunk diameter.

EZ Start® Potted Trees

Trees in bottomless pots that allow some roots to be air pruned, so that a dense mass of productive, feeder roots can grow within the pot to make transplanting easier. Mature sizes vary. When shipped, they are about 1-2' tall.

Select EZ Start® Potted Trees

Top-grade, potted trees chosen to give you a head start on growing. When shipped to you, they are about 3-4' tall.

*Tree sizes may vary by variety. See our Growing Guide for details.