Growing Raspberries

in Southern Wisconsin

Lisa Johnson, Dane County UWEX

Raspberry

• Raspberry Plant Anatomy

• Cultivar Selection

• Site Selection, Planting

• Fertilizer application

• Cane Support Systems

• Pruning

• Mulch and Winter Protection

• Major Diseases and Insects

• Further Resources

Raspberry Plant Anatomy

• Woody perennial

– Crown

– Roots

– Canes: Primocanes & floricanes

• Primocanes: first year non-fruiting

canes on summer-bearing cultivars OR

fruiting canes on fall-bearing cultivars

• Floricanes: Second year fruiting canes

on summer-bearing cultivars)

– Leaves

– Flowers (borne in clusters on lateral stems)

• Plants are most productive for 8-10 years

Tips Floricanes

Primocanes

Side Branches

Crown

RootsCrown Buds

Raspberry Plant Anatomy

Immature

Buds

Fruit buds

Leader Bud

Roots

70%

20%

6%

4%

Raspberry Plant Anatomy

StigmaStyle

Anther

Filament

Ovule

Receptacle

Raspberry Flower Structure

• Flowers are borne at

the end of lateral

shoots

• Flowers are self fruitful,

bees do 80-90% of

pollinating

• Aggregate Fruits—poor

pollination affects fruit

quality greatly. If each

carpel is not pollinated,

it doesn’t fill out

Raspberry Flowers and Fruit

Summer-bearing Raspberry Fruiting Habits

• Produce fruit on two year old canes (floricanes)

• Canes must be winter hardy in order to fruit the next

year (hardiness is important in cultivar selection!)

• Need short days, cool temperatures to initiate flowers

• Produce one crop in summer; floricane dies after

fruiting (can remove canes after bearing)

• If using heading back cuts to control height, don’t

remove more than 25% of cane

• New canes sprout from underground root buds

(‘leader’ buds)

• Planting can spread over time due to rhizomatic roots

Recommended Summer-bearing Cultivars

Cultivar Cultivar

Hardiness

Harvest

Season

Productivity Fruit

Size

Attractiveness Firmness Flavor Freezing

Quality

Boyne Very

good

Early Very good Medium Fair Fair Good Very

good

Nova Good Early Very good Medium

-large

Very good Good Very

good

Very

good

Prelude Fair Early Good Medium Good Good Very

good

Good

Latham Excellent Mid Very good Medium

-large

Very good Good Good Very

good

Kilarney Excellent Mid Very good Medium

-large

Excellent Good Very

good

Good

Haida Good Late Very good Medium Excellent Excellent Very

good

Very

good

Source: University of Minnesota

http://www.extension.umn.edu/distribution/horticulture/DG1108.html

Fall-bearing Raspberry Fruiting Habits

• Fruit borne on one-year-old (current) canes (primocanes)

• Day length, temperature don’t affect flower initiation

• Initiate flowers June-July; produce flowers early July-Aug.

• Fruits produced late August/September to frost

• Fruiting zone (where fruits are produced) starts at tip of

the flower cluster and moves from top of cane down

• Hardiness not an issue: canes don’t have to overwinter

• Pruning is easier (don’t have to thin twice, only once)

• More problems with spotted wing drosophila than

summer-bearing raspberries (so far!)

Recommended Fall-bearing Cultivars

Cultivar Cultivar

Hardiness

Harvest

Season

Productivity Fruit

Size

Attractiveness Firmness Flavor Freezing

Quality

Autumn

Bliss

Fair Early Very good Large Very good Fair Very

good

Very

good

Polana Good Early Excellent Medium Very good Fair Fair Good

Autumn

Britten

Fair Early Very good Large Very good Very

good

Excellent ---------

Josephine Fair Mid Excellent Large Very good Very

good

Very

good

---------

Caroline Fair Late Fair Large Very good Very

good

Very

good

---------

Heritage Very

good

Late Fair Medium Very good Very

good

Very

good

Good

Source: University of Minnesotahttp://www.extension.umn.edu/distribution/horticulture/DG1108.html

Raspberry Site Selection

• Good air circulation but protected site from wind

• Reduces leaf damage and dries faster after rain

• If possible, plant on a slight slope for cold air drainage

• Summer bearing- north facing slope

• Fall bearing- south facing slope

• Well drained mineral soil (not muck or heavy clay)

• Ideal: deep sandy loam with 5-7% organic matter

and a pH of 6.0-6.8 (optimal), can tolerate 5.5-7.5

• Avoid siting your raspberries where potatoes, peppers,

tomatoes, eggplant, other caneberries, or strawberries

have grown within the past 3 years.

Planting Raspberries

• Plant in the spring after danger

of frost is passed

• Plant at same depth as in

nursery—at old ‘soil line’ or so

‘leader buds’ are 1-2” under

ground

• Make sure roots are spreading,

not spiraling

• Water right after planting

• If using row planting, plant rows

18” wide, with 2 feet between

plants and 8 between rows

Fertility• Established plants: 4 to 5 pounds of 10-10-10

fertilizer for each 100 feet of row. Apply half in early May and half in early June

• If your soil test indicates high phosphorus and potassium levels, use 1½ to 2 lbs urea per 100 feet of row instead (same timing). DO NOT over-fertilize with nitrogen; plants may become more susceptible to fungal diseases

• Do not fertilize after August 1; Late spring or summer fertilization encourages succulent, late season growth which is susceptible to winter damage.

• New plantings: Divide the total amount for the season into thirds, and apply the first third 2 weeks after planting, the next third 1 month later, and the final third an additional month later.

• Manure may be used as an organic alternative. fertilizers. Apply 50 to 100 pounds of well-rotted barnyard manure (cow or horse) per 100 feet of row and work lightly into soil

• Plants 2-3 feet apart in rows

• Rows 6-10 feet apart

Raspberry Trellising Systems

Row

system: for

narrow rows

only

Raspberry Trellising Systems

T-stake system for

wider rows

Raspberry Trellising Systems

V-Supports

Pruning:

Cutting

Edge

Humor

Moral of the story: use sharp pruners

Pruning Summer-bearing Raspberries

• Two times

• Late summer after bearing

– Remove ‘finished’ floricanes by cutting

down to ground level (they will not

fruit again)

– Thin out new shoots to 4-6 canes per

foot of row

• Dormant Season

– ‘Head back’ primocanes by 25%

– Cut back side branches slightly (no

more than 25%)

– Remove weak, diseased or damaged

wood

– Thin primocanes to 4-6 per foot of row

Heading Back

Summer-bearing

Raspberries

• Take no more than

25% off the tips

• Encourages more

branching

Pruning Fall-bearing Raspberries

• Once (unless pruning for a small summer crop as well as a larger one in fall)

• Dormant (late fall or early spring)

• Cut back all canes to the ground

• Can use a mower if blades are sharp enough to make clean cuts

• Can use floating row cover in spring to hold in heat and start harvesting 5-15 days earlier. Remove covers when temps reach 80ºF or canes reach 12-18” in height (whichever comes first)

• Thin canes to 4-6 per foot of row once they are 6” tall or so

BEFORE AFTER

Thinning Canes (both Summer & Fall-bearing

Thin to 4-6 canes per foot of row

BEFORE

AFTER

Mulching and Winter Protection

• Using mulch is desirable for:

– Retaining moisture

– Protecting roots

– Reducing weeds

• Shredded bark mulch, straw

• May need to use a little more nitrogen fertilizer

as a result

• Winter Protection

– From rabbits!

– Chicken wire or hardware cloth (ideally 36”)

Raspberry Diseases

Root and crown rots (Soil borne. Occurs where soil is too heavy and drainage is poor, or due to poor pruning practices)

Pruning cuts

Raspberry Diseases

Cane Blight (fungal,

usually enters through

wounds)

Spur Blight (fungal,

usually enters through

leaves and then to canes)

Raspberry Diseases

Anthracnose (fungal, can attack leaves and

stems, hard to control—no fungicides effective)

Raspberry Insect Pests

Japanese Beetles

• Hand pick in evening or early morning

• Don’t use Japanese beetle traps

• No silver bullet

Raspberry Insect PestsSpotted Wing Drosophila

Raspberry Insect Pests

Raspberry Cane Borer

Resources

• UWEX Learning Store (http://learningstore.uwex.edu/)

• Growing Raspberries in Wisconsin A1610

• Midwest Fruit Pest Management Guide A4104

• Raspberry Pest Management for Home Gardeners

A2128

• Plant Disease Diagnostic Clinic Website

(http://labs.russell.wisc.edu/pddc/)

• Cane Blight XHT1242

• Raspberry Anthracnose XHT1232

• Root and Crown Rots in the Garden XHT1072

• Spotted Wing Drosophila XHT1237

• Japanese Beetle XHT1062

Thank You!

For a copy of this presentation, or to ask a

horticulture question, call or email

Lisa Johnson

Dane County UWEX Horticulture Educator

608-224-3715

Johnson.lisa@countyofdane.com

or see me at the Extension Booth

at the front of the hall