Recently, I was out of the country attending an agricultural
conference in Nairobi, Kenya. While there, I gave a presentation about
the many uses for bamboo and the benefits of establishing bamboo
plantations.

When I returned home, I found a lot of questions in my e-mail in-box
from readers of this column. I had to smile when I realized that the
first one I opened was about... bamboo!

QUESTION: "Can you please tell me approx how many feet the green panda
and the green screen grow each year and about how long it takes for
them to reach maturity?" - Susan Rodriguez

ANSWER: Bamboo is the tallest growing grass in the world. It does get
off to a slow start by taking at least three years to establish itself
(with minimum growth). Once the mother plant has established itself,
growth will gradually become faster with each cane becoming denser
than the previous. On an established plant, the canes will reach their
destined height in one year.

The bamboo variety known as green panda grows in the 6-10 foot height
range and the green screen grows in the 10-20 foot tall range. Bamboo
typically lives until the plant itself blooms, which is generally in
40 to 60 years.

QUESTION: "I purchased 50 Red Twig Dogwoods 3 years ago. They are
doing great. We live in [USDA Plant Hardiness] zone 7 and I just
trimmed them back some. What kind of fertilizer should I use on them
this spring? Also, what is a good fertilizer for Hemlocks, Compacta
Hollies and Nandinas?" -- Jerry Schaufenbuel

ANSWER: Since they are doing well, I would advise you to be cautious
in applying anything to them. Rather than fertilizer, you might just
mulch them with an aged compost mix or other organic matter to give
them any nutrients they might need.

If you feel that a fertilizer is necessary, use a low grade balanced
one and use sparingly. Fertilizer balances out the soil and is usually
only necessary when the soil is somewhat lacking.

For the hemlocks, I would add organic matter. Alternatively, visit
your hardware or garden store and ask for a fertilizer specifically
for evergreens such as hemlock and see what their best brand will be.
Take a pitchfork and punch holes around the base of the trees
spreading outward as the root system will spread out and not down.
Then spread fertilizer as directed and water.

The same applies to the holly and nandina plants, as they prefer
organic matter to inorganic fertilizer. However, for inorganic use,
there is a product called HollyTone that is used on broadleaf
evergreens (holly and nandinas).

As long as the plants are happy and growing, as I mentioned before,
just be cautious in your applications and follow the directions on the
packaging.

QUESTION: "I enjoyed your recent column about Knockout roses. I
planted a couple of Red Knockout roses last spring. They have done
pretty well. However Japanese beetles enjoyed feasting on them for a
few weeks. When the beetles left the plants recovered pretty quickly.
Should I trim the plants back during the cold months? Also, is this a
good time to trim weigela bushes? I don't want them to get too large."
- Barbara Moses

ANSWER: The Red Knockout roses are just fabulous, aren't they? A
product called Take Down Garden Spray works great on those little
beetles. Be sure to spray around the base of the plants as well as the
beetles burrow into the ground to reproduce. Actually if you have a
severe problem with the Japanese beetles, it may take 1-2 years of
spraying to break their cycle.

On a warm weekend in March, you may want to do your springclean up. On
the knockouts and weigela, as well as other plants, prune out any
branches that are broken, dead or crossing over each other. It is also
a good time for shaping to your liking as you can see the plant
without leaves to block the view.

Weigela can be pruned and shaped in early spring and then pruned again
after blooming. It is possible that they may bloom again after the
second pruning. But more, it keeps them to the size you prefer.

The Plant Man is here to help. Send your questions about trees, shrubs
and landscaping to and for resources and
additional information, or to subscribe to Steve's free e-mailed
newsletter, visit www.landsteward.org