How to Grow and Care for Boysenberry Plants

boysenberries

Quick Overview

Plant Type: Perennial
Family: Rosaceae
Sun Exposure: Full sun
Watering: Abundant water
Colors:
Size: 5-6 feet height
Hardiness Zones: 5–9
Soil Type: Well-drained soil
Soil pH: Slightly acidic
Propagation: Stem or root cutting, tip layering
Toxicity: Non-toxic

Boysenberries are a hybrid of raspberries and blackberries.  They are members of the rose family and of the genus Rubus.  Boysenberries are often referred to as brambles since they all have thorns.  Another name is cane fruits.  Whatever you call them, boysenberries are delicious.  

Boysenberries grow best in full sun.  Boysenberry plants can live a decade so make sure you plant them someplace they can stay in for that long.  Boysenberries need well-drained soil and often do well in raised beds.  They do need supplemental water and fertilizer, especially the first year. 

Boysenberries are not hard to grow if you meet their requirements on a few things.  This article will take a look at those things.  

Boysenberry Plants

Growing Boysenberries  

Boysenberries are black and are made up of drupelets, or individual fruits with a seed each in them.  They look like blackberries and the fruit is about the size of a large blackberry.  

Do Boysenberries Grow on a Bush or a Tree?  

Boysenberries grow on canes arising from a perennial crown.  These canes trail on the ground unless trellised. They usually have thorns, but there are some thornless varieties.  First-year canes are called primocanes and second-year canes are called floricanes.  Berries are produced on floricanes.  These canes can grow up to 15 feet long.  Canes produce about a quart of berries per linear foot.  

There is more to growing boysenberries than just sticking them in the ground.  The site must be selected and prepared.  The boysenberries have to be cared for properly to produce good berries.  Here is everything you need to know to grow berries that taste great for years to come.  

Site Selection  

Boysenberry plants can live over a decade, so make sure you put them somewhere they can stay that long.  The site needs full sun, well-drained soil, with good access to water.  Boysenberries can tolerate wet, heavy soil but do much better in lighter soils.  Raised beds are a good option, as the roots usually stay in the top 20 inches of soil.    

Boysenberries Variety Choice  

Purchase certified virus-free stock from a reputable grower.  Planting bare root varieties in the early spring is better than planting potted plants.  Order your plants early so you will get a good selection of plants.  The Extension service in your county can tell you which varieties do the best in your area.  

Site Preparation  

Boysenberries prefer soils with a pH of 5.5-6.5, which is slightly acidic.  Test your soil a year before planting to see what the natural pH in your area is.  You can add elemental sulphur to the ground and till it in to make the ground more acidic.  It takes six months to a year to lower the pH.  

Building The Trellis  

Boysenberries should be trained on a trellis as if they were trailing blackberries.  The easiest way to do this is to put a large wooden or metal post (3-4 inches in diameter and 6 feet high) at both ends of the row.  Put metal T posts in every 15-20 feet.  Run 12-gauge wire along the top of the posts and attach the wire to each post.  Put a wire tightener on each end of the wire.  Run a second wire about knee height.  The bottom wire should be on S hooks and not permanently attached to the posts.    

Planting  Boysenberries

Plant boysenberries four to six feet apart.  Rows should be about 10 feet apart.  Plant them against a trellis T post.  Plant the crowns under one inch of dirt.  Trim the canes to two inches long to stimulate the crown to grow new canes.  Water the boysenberries in.  

Boysenberries

Can Boysenberries Grow in Pots?  

Boysenberries can grow in pots, if the pot is at least 25 inches deep and around two feet in diameter.  While a half whiskey barrel works, the canes will grow long and spread out from the container.  It is really better to plant the berries in the ground.  If you do decide to use a barrel, place an acidic soil mixture in there. Plant your boysenberry plant with an inch of dirt over the crown and trim the canes to two inches long.  Water the plant in.  

Boysenberries General Care  

Once the boysenberries are planted, they require a certain level of care.  Here are the particulars.  

Water 

Newly planted boysenberries need an inch of water every five days from planting until they go dormant in the late fall.  Plants one-year-old and older need an inch of water a week from early spring through late fall.  If you live in hot water, switch back to watering every 5-days when it gets hot.  In the winter, water once a month on a warm, sunny day.  

Fertilizer 

Every year, before the growing season starts, have a soil test done.  You can get sample bags and instructions from your Extension agent.  Fertilize according to the soil test results.  Otherwise, fertilize the newly planted boysenberries with a balanced 10-10-10 fertilizer. Give it to the plants two weeks after planting, then a month after that, then a month after that.  In the second and following years, fertilize with a balanced fertilizer such as 16-16-16 in early spring as new growth starts.  

Pollination

 Boysenberries are self-pollinating.  However, the fruit is bigger when the flower is pollinated by a bee.  Native bees sometimes use the hollow stems to nest in.  

Mulching

 By mulching around the plants after the soil warms, you can help keep weeds out of the cane patch.  The mulch also helps keep moisture in and the soil cooler when it is hot.  You will need to put down about three inches of mulch.  When you do, put some Nitrogen fertilizer on the mulch so it will not take the Nitrogen the plant needs.  Do not use plastic mulch cloth or weed barrier fabric as this will prevent the primocanes from growing out of the crown.  

Boysenberries

Pruning and Training Boysenberries

 You do not have to prune your berries or train them to grow on a trellis.  If you do not do so, you will have a bramble patch which makes it hard to reach all the berries.  Training the plant to trellis leaves a clean row where you can reach most of the berries without a problem.  It also cuts down on snakes and other wildlife that might injure you when you are harvesting the fruit.  

The first year boysenberries are grown, train the canes up the trellis.  Bundle them together and tie them with twine.  Do not use plastic or wire as it will cut the canes.  If the canes reach the top of the trellis, weave them in between the top wire and the lower wire and spread them out.    

The second year, and all years after this, you will have the floricans on the wires.  The primocanes should be laid under the wire lowest wire on the ground.  In autumn, after the flowers on the floricanes and any fruit are done, the floricanes will die.  Prune them out at this point.  Remove those canes from the wires.  Lift the primocanes up onto the wires and weave them in between the two wires.  

Boysenberries Diseases  

Boysenberries are prone to numerous diseases.  Not all diseases are problems in all locations.  If your boysenberry has a disease and you cannot identify it, take a sample to your Extension agent. They will be able to identify it and tell you how to get rid of it. 

  • Algal Spot: Light green to light orange spots appear on the cane and slowly take over the entire cane.  
  • Cane and leaf spot: Small lemon yellow sores appear on the canes and leaves.  The canes crack and dry and the leaves dry out.  Cut off the canes and burn them or place them in the trash.  
  • Orange rust: This starts as small yellow spots on both sides of the leaf.  On the underside of the leaf, these join into large pustules.  These burst to reveal large quantities of orange spores.  Remove the plant and destroy it.  
  • Yellow rust: This is similar to orange rust, but the spots stay yellow.  Canes tend to dry out and crack, while leaves release large amounts of yellow spores.  
  • Anthracnose: In the spring, there are small purplish spots on the canes and spots with purple margins on the leaves.  The spots on the canes become oval, enlarge, and cause the cane to die back.  
  • Fruit rot: There are many kinds of fruit rot.  They are mainly fungal and grow best in wet, mild weather.  
  • Cane Gall, Crown Gall, and Hairy Root Cane: Cane galls form long, cane-splitting masses.  Crown galls are large galls on the crown or upper roots.  Hairy root is small, fine roots coming out of the lower cane.  All plants with these problems need to be destroyed.  Do not replant boysenberries there.  
  • Septoria Leafspot: This starts with small spots on the leaves with tan centers.  The spots tend to remain small and do not cause any major problems.  
  • Verticillium Wilt: Boysenberries are highly susceptible to this disease.  The disease starts at the bottom of canes and works its way up.  First year canes have leaves that turn pale green, then yellow.  They fall off early.  Second year canes have leaves turn yellow and wilt.  This kills the plants in one to three years.  
Boysenberries

Pests  

There are several pests that eat boysenberries.  It is important to know which pest you have so you know how to treat it.  Take a sample and submit it to your Extension agent.  They will be able to identify it for you and suggest a treatment.  

  • Spotted wing drosophila: This is an invasive species that lays eggs in the developing fruit.  The larvae eat the fruit from the inside out.  The populations build up as the season progresses, so late maturing fruit is more vulnerable.  
  • Brown marmorated stink bug: This is another invasive species that punctures the fruit.  Their population also increases toward the end of the summer.  They are brown true bugs that give off an offensive odor when threatened.  
  • Apple pandemis, light brown apple moth, omnivorous leafroller, and orange tortrix moths: All of these moths lay eggs on boysenberries. The larvae feed on foliage, where the damage is usually minor, and fruit, which ruins them.  The larvae are all similar and are white caterpillars with dark heads.  
  • Raspberry crown borer: This is a stout moth that looks like a yellow jacket.  The larvae tunnel into the crown, upper roots, and cane.  This causes the cane to wilt and break off.  The larvae are white with a dark head.  
  • Red berry mite: This mite is microscopic.  It injects a toxin as it feeds that prevents that section of boysenberry from ripening.  It also distorts the flavor.  Once you notice the damage, that season’s crop is already ruined.   
Boysenberries

Harvesting 

The boysenberries will not have fruit the first year they are in the ground.  They will have a small harvest the second year.  From the third year on they will have a normal harvest.  When the boysenberries start to ripen, begin harvesting once a day.  Only pick the ripe fruit as they will not ripen once picked.  Picking daily helps keep insects and animals from being drawn to the overly ripe fruit.  Be aware that snakes, including poisonous copperhead snakes, love berries.  Watch where you are putting your hand.  It is wise to wear gloves when harvesting to protect against the thorns.  The fruit is fragile and only keep s a few days so refrigerate immediately.  You can freeze the berries by putting them in one layer on a cookie sheet and putting them in the freezer.  After they are frozen, put them in a zip close freezer bag so they do not take up so much room.  

In Conclusion

Boysenberries are a delicious fruit that is not hard to grow. This hybrid of blackberries and raspberries acts more like a trailing blackberry than a raspberry. A boysenberry patch can last over a decade and produce a quart of boysenberries per linear foot of canes. The canes can each grow to be 15 feet long, so it does not take a lot of plants to have lots of berries.