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Question
Help!! Aphids have taken over my rose garden and they are everywhere.
What do I do?
Answer
Almost any insecticide will kill aphids. Insecticidal soap is
environmentally friendly and works well and will not damage your rose
flowers. A strong spray with a garden hose will also wash away most of
the aphids and they seem not to crawl back. If you happen to see some
lady bugs in your garden, in a few days they will devour an incredible
number of aphids. You should use nothing stronger than a water spray to
protect the lady bugs while they are eating.
Question
Can you suggest a low-growing, evergreen ground cover for sun; preferably
one that blooms?
Answer
There are not a lot of choices. My favorite is still Hypericum calycinum
(St. John’s Wort). However
this can be a difficult plant to establish. Bareroot does not work at all
and flatted plants in peat pots usually have poor survival. You are much
better with well-established, potted quart-size plants. They cost more
but you can plant them on 18 inch centers and have solid coverage in 2
years. Hypericum blooms in July with yellow flowers and grows about a
foot tall. The leaf has a handsome bluish-gray cast. Hypericum spreads
underground so it does not make a viney mess like some ground covers. It
is resistant to both deer and road salt. However in a tough winter, it
can lose some, if not all of its leaves - in which case it should be cut
back to the ground in early spring for vigorous re-sprouting. Once
established, it is a tough, tough ground cover.
I have seen Vinca
minor (periwinkle, myrtle) do well and retain its deep green color in full
sun. Vinca is usually only recommended for light shade. However with
adequate soil preparation, it will thrive in full sun and of course it is
totally evergreen in winter. Additionally, it is very low-growing;
only 1-2 inches tall.
A third choice for a
place with perfect drainage is the perennial Geranium cantabrigiense.
This geranium is about 3/4 evergreen and has deep pink blooms in
May/June. It will grow in full sun or light shade. The fragrant foliage
is deer resistant, but I reiterate it must have excellent drainage.
Question
Is it too early to cut back the daffodil foliage?
Answer
For adequate performance, the foliage on daffodils must remain 6 weeks
after flowering. Thus, the foliage can be cut back at this time.
However, for top notch performance you should leave the foliage until it
starts to brown, usually in July. Incidentally, did you remember to
remove the seed heads from the daffodils after they finished blooming?
Also, daffodil
foliage should never be tied in knots; it may make the garden look neater,
but the purpose of the foliage is to gather sunlight to nurture the bulb
for next spring’s bloom. Foliage that is tied is not adequately exposed
to the sunlight.
Question
I want to plant some trees that are native to
Maryland. Can you help me with a list
of trees?
D.V.
Glen Burnie,
MD
Answer
Consider: red bud,
Florida dogwood, sweet bay magnolia,
fruitless sweet gum, pin oak, American holly,
Virginia witch hazel, silver bell,
serviceberry, red oak, scarlet oak, fringe tree, red maple, sugar maple
and heritage birch.
Question
When is the best time to trim back irises after they have bloomed? How
far back should they be cut?
S.N.
Cincinnati,
OH
Answer
You can cut the bloom stalk out right after the irises finish blooming.
The leaves never need to be cut back for the health of the plant. Often,
by mid-summer, the leaf-tips start to brown and look unsightly. At that
time (usually early August), you can cut the irises back halfway.
Question
I love peony blooms, but the plant flops all over and by mid-summer the
foliage is spotted and ugly. I am a low-maintenance gardener and I do not
have time for spraying and peony rings. What do you suggest?
Answer
Consider the peony “Karl Rosenfeld”; the bloom color is a very deep, deep
pink - almost red. It’s an old timer that stands erect and has lush foliage
that remains clean throughout the season. It makes a beautiful display in
the garden. Just don’t count on it for lots of fragrance.
Question
My hostas look beautiful in the spring, the foliage is white and green,
but by mid-summer even with adequate watering they always turn brown and
ugly.
Answer
I suspect you have the old fashioned Hosta undulata univittata, which is
the one you see everywhere, with the white centers edged in spring with
green. But as the season progresses the green becomes predominant.
Adequate moisture, afternoon shade and occasional spraying with a
fungicide will help some, but these are merely partial solutions.
I suggest you
consider the Hosta “Halcyon” which has thick “blue” leaves that resist
slugs and that persist until October. By the end of summer most of the
blue will have disappeared, but the foliage remains a crisp dark green
even after a light frost.
Many of the newer
hostas will also perform better in the summer than the one you have. But
of the lower priced hostas, Halcyon is just about the best for fall
foliage appearance. |
