University of Vermont Extension
Department of Plant and Soil Science
Spring News
Article
SPRAYING DORMANT OIL
AND OTHER APRIL GARDENING TIPS
Charlie Nardozzi, Senior
Horticulturist
National Gardening
Association, and
Dr. Leonard Perry, Extension
Professor
University of Vermont
Spraying dormant oil, sowing
early crops, and preventing weed germination in lawns, are some of the
gardening tips for this month.
If scale or aphids have been a
problem on trees and shrubs, get the dormant oil spray ready for a day
above 40
degrees with no wind. Coat the branches, and repeat if directed on the
label.
Early spring, when young scales are in the crawler stage, is the best
time to
control these pests.
The first crops that can be sown in
the ground once the soil has dried out enough are beets, carrots,
lettuce,
parsley, peas, radishes, spinach, and Swiss chard. Plan to make
successive
sowings to prolong the harvest.
Once the soil reaches 45 degrees and
is dried out enough to dig, it's time to plant peas. Choose a location
in full
sun and orient the rows north-south to take full advantage of the
sunlight.
Turn over the soil with a garden fork, or rototill if it's a new bed.
Soak the
seeds for a few hours or overnight (no longer or they may rot), and
dust the
seeds with an inoculant of nitrogen-fixing bacteria to help the roots
take in
more nitrogen. You can find this inoculant online or at many full
service
garden centers.
Set
up your pea trellis first, then plant the seeds 1 to 2 inches deep.
Cultivate
very
shallowly because
the roots grow close to the surface; better yet, pull the weeds by hand
so you
don't accidentally cut off a plant.
Moving a woody plant before it
begins new spring growth causes less stress on the plant, so try to do
this
type of transplanting as soon as the soil is workable. The larger the
plant,
the more the timing matters.
Before annual crabgrass and other
lawn weeds germinate this spring, spread corn gluten pre-emergent
herbicide/fertilizer with a lawn spreader. The corn gluten suppresses
seed
germination and also provides nutrients to the grass. Use the blooming
time of
forsythia to signal that it's time to spread the crabgrass control.
If you have dead spots in the lawn,
plan to patch them before the summer heat. Loosen the soil and work in
some
good quality compost, sprinkle grass seed, rake lightly, and tamp to
assure
good seed-to-soil contact. Mulch with a thin layer of straw. Water as
needed to
keep the soil evenly moist until the grass sprouts.
Woody perennials differ in the way
they should be cut back in spring. If butterfly bush has died to the
ground,
cut the dead stems to the ground. Otherwise just shorten them by about
one-third. Cut back Russian sage, rue, and artemisias to about 8 to 12
inches
from the ground. Don't prune lavender until new growth appears and then
just
shorten the stems by about one-third. Heather should be lightly pruned
to
remove the old flowers and the tips of the shoots, but don't cut back
to brown
wood, stay in the green. Prune spring-flowering shrubs such as
forsythia and
lilac right after they bloom.
Return to Perry's Perennial
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