Thornless blackberries for the home garden


Material Information

Thornless blackberries for the home garden
Series Title:
Home and garden bulletin ;
Physical Description:
6 p. : ill. ; 23 cm.
Hull, J. W
U.S. Dept. of Agriculture
Place of Publication:
Washington, D.C
Publication Date:


Subjects / Keywords:
Blackberries   ( lcsh )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Statement of Responsibility:
prepared by J.W. Hull.
General Note:
Cover title.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 004931670
oclc - 16734739
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Thornless blackberry varieties --------------------------- 1
Planting sites 1----------------------------------------- 1
Preparing the soil ------------------------------------ 1
Spacing the plants-------------------------------- 2
Setting the plants---------------------------------- 2
Intercropping 2----------------------------------------- 2
Trellis construction ------------------------------------ 2
Training ---------------------------------------------- 3
Pruning----------------------------------------------- 3
Fertilizing and watering------------------------------- 3
Cultivation-----------------------------------------_ 4
Cover crops----------------------------------------- 4
Herbicides----------------------------------------- 4
Harvesting------------------------------------------- 4
Preventing winter injury----------------------------- 5
Diseases and insects---------------------------------- 5
Descriptions of thornless blackberries 5------------------ 5

Cover: Thornfree blackberry plant. This plant requiircs little summer
pruning, and is the most winter hardy thornless variety.

Washington, D.C. Issued May 1973

For sale by the Superintendent of Documents
U.S. Government Printing Office, WDihmi ..ii. D.C. 20402
Price 20 cents domestic postpaid or 1"I cLiii P 'O Bookstore
Stock Number 0100 02751



Prepared by J. W. HULL
Plant Genetics and Germplasm Institute
Agricultural Research Service

' For years home gardeners hesi-
tated to grow blackberries in their
backyard because of the annoyance
of the thorns. Then two thornless
blackberry varieties-Smoothstem
and Thornfree-were developed by
the U.S. Department of Agricul-
ture. Popular with home gardeners
and proprietors of "you-pick" en-
terprises, these productive black-
berries are easy to handle and re-
quire little summer pruning. The
fruits are firm and highly flavored.


Both Smoothstem and Thornfree
are genetically thornless blackber-
ries-all the cells are thornless.
When new canes develop they re-
tain this thornless characteristic.
Other thornless blackberries, such
as Thornless Young, Thornless Lo-
gan, and Thornless Evergreen, have
a thornless character only in the
outer cell layer of their canes. New
canes originating from their roots
have thorns.
Thornless blackhrL rijes have trail-
ing or semitrailing canes that are
not self-supporting. They can be
grown along the ground in their

first season, but, thereafter, must be
trained on trellises.
Blackberries are planted in early
spring in the North; in late winter
or early spring in the South.
Blackberries vary in their ability
to withstand cold, and none should
be grown without special winter
protection in areas where tempera-
tures drop to 00 F. and below.

Planting sites for blackberries
must offer plenty of soil moisture.
This condition is especially neces-
sary while the fruit is growing and
Almost any soil type, except very
sandy soil, is suitable for black-
berries if the drainage is good-
both on the surface. and in the soil.
Plants can be harmed at any season
of the year if water stands around
their roots.
Preparing the Soil
Prepare the soil as you would for
a vegetable or flower garden.
If you are establishing a new
planting, seed and plow under one
or two green-manure crops of cow-
peas or of rye and retch. This will
condition the soil, and the added or-

ganic matter and nitrogen will help
produce an early .fruit crop.
Spacing the Plants
Leave plenty of space between
rows when planting blackberries, or
severe competition for soil nutrients
and moisture will result.
Smoothstem and Thornfree are
vigorous varieties and should be set
6 to 8 feet apart in rows that are at
least 8 feet apart.
Less vigorous varieties, such as
Thornless Young and Thornless Lo-
gan, should be set 4 to 6 feet apart
in rows that are at least 8 feet apart.
Aline plants carefully in the row
to accommodate the trellis, which
will be constructed. (See p. 2.)
Setting the Plants
Do not let planting stock dry out.
This condition can be prevented by
heeling in the roots.
To heel in, dig a trench in a
shaded area deep enough to hold
the roots. Open the bundles and
spread the plants along the trench
with the roots down. Cover the
roots with moist soil and firm the
soil down to eliminate air pockets.
If the plants are dry upon arri-
val, soak the roots in water for sev-
eral hours before planting or heel-
ing in.
If you do not plant im-
medi:itely, wrap the plants in poly-
ethylene bags and place them in a
refrigerator until planting time.
Before setting the plants, cut the
tops (the old cane or "handler)
back to about 6 inches. This is use-
ful for handling the plants and
serves to mark their location.
After you make a planting hole,
set the root of the plant so that it is

about the same depth as it was in
the nursery, or slightly deeper.
Then firm the soil carefully to as-
sure good contact with the roots.

During the first summer after
setting the blackberries, vegetables
such as beans, peas, or cabbage can
be grown in the spaces between
rows. Their cultivation will benefit
the blackberry plants and put the
unused portion of your garden to
good use.
Intercropping should not be
done more than once; when the
blackberry plants are of bearing
size they will need all available
moisture and nutrients.

After the first season, thornless
blackberries should be trained on
trellises. This will assure clean
fruit, ease of picking, and help in
disease control.
Many trellis arrangements and
training methods are satisfactory.
To construct a simple and effective
Stretch two wires (gage size
12 or 14) between end posts set 15
to 25 feet apart in the row. String
one wire 21/2 feet from the ground
and the other about 5 feet from the
Staple the wires to all posts
between the end posts. (Wires must
be loose enough to allow for con-
traction in cold weather.)
Tie trailing canes horizontally
along the wires or fan them out
from the ground and tie them
where they cross each wire. Avoid
tying the canes in bundles.


Thornless blackberries should be trained on a two-wire trelliA. Set end posts 15 to 25

feet apart in the row. Siring one wire
about 5 feet from the ground.


During the first year, blackberry
canes grow vegetatively and send
out side branches. In the second
year, these canes bear fruit, and
then the canes die. (The canles aris-
ing from the crown are biennial;
they live for only 2 years. The roots
and crowns are perennial.)
Methods of t ringing blackberries
largely depend on the length of the
growing season and the degree of
winter cold.
In northern areas, leave trailing
varieties of thornle ,- blackberry
canes on the ground, under the trel-
lis, until their second svea on. Then,
before the buds swell, bring the
canes up to the trellis wires, wrap
them in groups of three or four, and
Tie senmit railing blackberry vari-
eties to the wires in their first year.
In the South, tie new canes of
both trailing and semitrailing vari-
ties to the trellis as soon as harvest
is over and old en lies have been re-

After harvest, prune away old
canes and destroy them as a sanita-

21 feet from the ground and the other

tion measure. In certain areas of the
South anthracnose and rosette, both
serious diseases of blackberries,
threaten crops. In these areas, all
the canes should be cut out after
Before tying caI's to the trellis
wire, remove any that are weak,
spindly, or broken.
Thin out to leave 12 to 16 new
canes. Tie these to wires, or depend-
ing on the management plan being
used, leave them under the trellis
for the rest of the season.
Thornfree and Smoothstem va-
rieties require little summer prun-
ing; they do not tend to branch
freely and usually will not develop
more than three or four canes.
Before growth starts in spring,
prune all side branches back to 12
inches. Side branches that are
pruned will produce larger fruit
than those that are not pruned.


Mixed .fertilizers are satisfactory
for blackberries. For best results,
apply fertilizer in early spring
when growth starts and again in
summer just after hai vest. Use a 10-

10-10 commercial fertilizer mix or
a 10-6-4 mix at the rate of 5 pounds
per 100-foot row.
For late-ripening varieties, such
as Smoothstem and Thornfree, ap-
ply the fertilizer mix no later than
July. This is to avoid forcing a late
season growth that will be subject
to winter injury.
For the first year or two, before
the root systems of the plants de-
velop fully, spread 3 or 4 ounces of
the fertilizer mix in a 12-inch radius
around the base of each plant.
Blackberry plants require plenty
of moisture while the berries are
growing and ripening. The amount
of water needed is roughly equiva-
lent to 1 inch of rainfall per week.
Irrigate sufficiently to meet this re-
Mulching reduces the .frequency
of watering. Good mulch materials
include: seed-free straw or prairie
hay, pine needles, corn-cob, wood
chips, or cotton hulls. Lawn clip-
pings are not satisfactory.

Blackberry plants need thorough
and frequent cultivation; weeds and
grasses compete for moisture and
are difficult to control.
Cultivate thornless blackberries
during the summer, and as often as
necessary to keeps the weeds down.
To avoid harming shallow roots of
the plants, cultivate only 2 or 3
inches deep near the rows. Unneces-
sary pruning of roots stunts plant
Discontinue cultivation at least a
month before freezing weather be-

Cover Crops
Winter cover crops planted be-
tween the rows help to maintain the
structure of the soil, and reduce
erosion. If a legume cover crop is
planted, valuable nitrogen will be
added to the soil.
Sow cover crops during the fall.
The following cover crops are
adapted to thornless blackberries:
field rye, vetch (a legume) and rye,
and spring oats.
Drill or broadcast the seed by
hand between rows. Plant at least
18 inches away from either side of
the row to allow air circulation for
the blackberry canes on the ground.
Herbicides can be useful, espe-
cially in large plantings. Control
recommenldat ions depend on soil
types, and weed species in various
areas. Contact your county agricul-
tural agent or State Agricultural
Experiment Station for local recom-

Blackberries that are picked at
the proper time, handled carefully,
and stored in a cool place will stay in
good condition for several days.
Overripe or injured berries spoil
Harvest thornless blackberries at
least twice a week, but do not pick
thornless blackberries as soon as
they turn black. It is better to wait
3 or 4 days and pick when the color4
has a dull appearance. This will
assure a better flavor, color, and
wholeness, especially if you are
canning the berries.
Remember the following when
harvesting the berries-

Pick berries in the morning
while the temperature is still cool.
Blackberries picked in the morning
do not spoil as easily as those picked
in the afternoon.
Pick carefully and do not
crush or bruise the fruit when plac-
ing them in berry baskets.
Pick when the berries are fully
ripened and firm.


Winter protection is needed for
blackberries in areas where winter
temperatures are expected to go be-
low 100 F. Cold-hardy varieties,
however, need no special protection
in the winter.
In areas with low winter temper-
atures and cold, drying winds,
cover the canes with a layer of soil,
straw, or coarse manure. This
should be done after the canes have
become dormant, and before the
onset of severe cold weather. Re-
move this protective layer before
growth starts in spring.
Where winters are mild and
moist, such as in western Oregon,
canes of trailing varieties left lying
on the ground will be damaged. It
is best, in areas with similar con-
ditions, to tie the canes to the trel-
lis in early fall and allow them to
Istay up through the winter. How-
ever, in areas with severe drying
winds, ca nes tied to trellises are
subject to winter injury.


Diseases and insects vary in kind
and severity from area to area. For
information suited to your local con-

editions contact your county agri-
cultural agent or State Agricultural
Experiment Station.
To keep disease and insect dam-
age to a minimum-
Choose disease-resistanti varie-
ties adapted to your area.
Destroy disi.asd plants.
Remove old canes soon after
Remove all wild blackberry
plants in the vicinity of your gar-
Prune out and burn canes that
have been in fested with insects.
Keep the garden free of weeds
and fallen leaves.


The thornless blahckberry varie-
ties that follow are listed in their
approximate order of ripening. Spe-
cific ripening dates will vary with
location and season. All the varie-
ties are partly susceptible to winter
The variety descriptions include:
the degree of hardiness (four de-
grees are given: Hardy, moderately
hardy, less hardy, and tender); the
duration of harvest; the character-
istics of the plant; and the area of
special adaptation.
For local variety recommenda-
tions consult your county agricul-
ural agent or your State Agricul-
tural Experiment Station.
Thornless Logan.-Less hardy;
harvest period is 10 to 15 days;
berry large, long, reddish, acid,
high flavor; plant is vigorous, very

prodi.ctive. Grown on Pacific coast.
Not adapted to East.
Austin Thornless.-Moderately
hardy; harvest period is 10 to 15
days; genetically thornless, berry is
large, round, black, good flavor;
plant is vigorous but only moder-
ately productive. Widely grown in
the South.
Thornless Young.-Moderately
hardy; harvest period is 10 to 15
days; berry large, soft, wine col-
ored, very sweet; plant is vigorous
and fairly productive. Adapted in
the South and Pacific States.
Cory Thornless.--Less hardy;
har\-vst period is 10 to 15 days;
berry large, black, sweet, soft; plant
is vigorous and fairly productive.
Grown on Pacific coast.
Thornless Boysen.-Moderately
hardy; harvest period is 10 to 15
days; berry large, soft, wine col-
ored, very sweet; plant is vigorous
and fairly productive. Adapted in
the South and on Pacific coast.

Thornfree.-Hardy, harvest pe-
riod lasts for about 1 month;
genetically thornless, berry me-
dium, firm, black, good flavor;
plant is notably healthy and very
productive. Grown in central New
Jersey, southern Pennsylvania,
southern Ohio southward to North
Carolina and west to Arkansas,
and in the Pacific Northwest.
Smoothstem.-M o d e r a t e 1 y
hardy; harvest, period lasts for
about 1 month; genetically thorn-
less, berry medium-large, black
good flavor; plant is extremely
healthy and vigorous, very produc-
tive. Adapted from southern Mary-
land to North Carolina along At-
lant ic coast.
Thornless Evergreen.-Hardy;
harvest period lasts for about 1
month; berry is large, exceptionally
firm, sweet, black; plant is vigor-
ous, productive, and healthy. Best
adapted to Pacific Northwest.

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3 1262 08582 9645


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