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 that 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 faraway 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 set up 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 that spring? additionally, 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 essential, use a low grade balanced one and use sparingly. Fertilizer balances out the soil and is usually only essential when the soil is somewhat lost.

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 make 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. next 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 lengthy 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? plus, is that a good date 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 certain to spray around the base of the plants as well as the beetles burrow into the ground to reproduce. Actually whether 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 by each other. It is plus a good duration 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 next 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 steve@landsteward.org and for resources and additional knowledge, or to subscribe to Steve’s free e-mailed newsletter, visit www.landsteward.org

Original post by Greenwood Nursery