April 4/13/2003

It seemed like the gardening season would never get underway this year.
But with the forsythia bushes and daffodils blooming I think we can
safely say spring is here!
Since the forsythia is in bloom, pre-emergent weed controls can be
applied to the lawn and shrub beds. Pre-emergents applied now can
greatly reduce the amount of time spent on weeding later on in the
season. Most of the pre-emergent controls are chemical based, but there
is an organic control made from corn gluten also available. Just
remember that you can’t use these products anywhere that new seed has
been or will be planted in the next eight weeks.
Over the past few weeks I have had several questions concerning the
planting of grass seed in shady conditions- specifically under mature
trees. When trying to grow grass under shade trees you should always
use
a specialized seed mix blended for shady areas. Spring is a good time
to
try growing grass under trees, provided that it isn’t dense shade. In
the spring before the tree leaves have grown there will be more
sunlight
available and no fallen leaves to cover the newly sprouted grass as
there is in the fall. But trying to grow grass under large mature trees
such as evergreens, maples and oaks is futile and a waste of resources.
The lack of sufficient sunlight and the tree’s strong root system are
an
unfriendly environment for growing grass. Selected removal of some of
the tree’s limbs will help to provide more sunlight to the grass.
Eventually growing grass under the tree will become impossible. It is
not recommended that you add a layer of soil to the area in order to
cover the tree roots and grow flowers. Any change to the grade of the
area under a mature tree will send that tree into a gradual decline,
eventually killing it. Spreading a 2-3 inch layer of much over the area
will keep mud down if it is a pathway. Containers of shade loving
annuals and a garden bench or statue can be a pretty alternative. The
bright side is –you won’t need to mow there anymore!
If you haven’t done so already, rake back the winter mulches and leaves
from around the perennials, rose bushes and spring bulbs. The
perennials
that bloom in the summer and fall can be divided now if they are
over-crowded. The perennial bed can be fertilized with 5-10-5 at a rate
of 2-3 pounds per 100 square feet. If you chose to use the fertilizer
Milorganite you will get the added bonus of a deer repellent. It needs
to be applied repeatedly throughout the season if used as a repellant.
April is the month to prune many varieties of the flowering vine
clematis. This popular vine blooms profusely during the summer months,
especially if pruned properly. The vines can be pruned back to within
36
inches of the soil or to a strong bud. Another plant that responds well
to proper pruning is the hydrangea. I often get questions regarding the
failure of this plant to bloom. The macrophylla types (the big-leafed
or
mop-head hydrangeas) are best pruned after they leaf out in the spring.
The hydrangeas leaf out later than most of the flowering shrubs. Just
trim back the top portion of the stems that fail to leaf out. That way
flower buds won’t be accidentally be removed.
With the pattern of cool damp weather we have had recently, it is
important to think about the probability of fungal leaf diseases on
some
trees and shrubs. Fungal spores are released during cool damp
conditions
in the spring. Susceptible plants won’t show the symptoms till a month
or two later. As the new leaves open the spores land and begin
infection. Later on spots or discoloration will start to cover the
leaves. Crabapples, fruit trees and rhododendrons are some plants that
are susceptible. Fungicides can be applied as the new leaves start
growing. They should be sprayed when there are 2-3 days of dry weather
forecasted for optimal effect. Follow the directions suggested on the
label. These sprays usually need to be re-applied at 10 and 20-day
intervals for prevention of disease.

Beth Nardone, botanist, is a resident of Hillsborough and is the
Nursery
Manager at the Belle Mead Co-Op. Questions and comments can be sent to
bethtanical@rcn.com