By Scott Aker
Special to The Washington Post
Thursday, April 16, 2009
Q I have a mature silver maple, a majestic tree that shades the house in summer and is a major reason I bought the property. However, its surface roots are unfriendly to other plants. Can you recommend low shrubs and ground covers or anything that will have a fighting chance in this environment?
A Little will grow under mature silver maple trees, primarily because they are so greedy for water and nutrients. They are weak-wooded and relatively short-lived, so if you are planning for future generations, I recommend underplanting with another tree to account for the maple's ultimate demise. White oak, black gum or hickory would have the mettle to compete with your silver maple if you can provide extra water in times of drought.
You can maintain a mulch of leaves under the tree in the bare areas, or you could plant a few tough perennials that will grow with the dry shade and root competition, including hellebores, epimedium or liriope. All of those will require additional water during drought to thrive.
My amaryllis has finished blooming and has grown leaves. What must I do to get it to bloom again next winter?
The key to year after year of flowers from your amaryllis is to keep the bulb growing and give it the proper cool treatment to stimulate the emergence of flowers.
Amaryllis is native to parts of South America that experience a long, warm wet season and a shorter, cool dry season. Inside the bulb, a new flower stalk is initiated after four or five leaves have grown. If you want two flower scapes, your goal this summer will be to grow eight to 10 healthy leaves. If you can manage to grow 15 leaves, you may get three flower scapes. The flower stalks will not emerge from the bulb until it has experienced a sufficiently long cool period.
When the weather has settled, move your potted amaryllis outdoors. Give it ample amounts of fertilizer beginning in late May or early June and keep the soil constantly moist. Leave it in full sun until the end of October. At this time, you can move your amaryllis under an eave or in another location that is sheltered from rain. Keep the bulb outdoors until heavy frost threatens. Then move it into a cool environment indoors so it can be maintained at a temperature around 50 to 60 degrees. The first signs of the flower stalks may appear near the end of the cool period, so check the bulb frequently.
When the new flower stalks begin to emerge, move the bulb into a sunny, warm position and keep it barely moist until the stems begin to elongate rapidly. You can water it more frequently when strong leaf growth is apparent. Simply continue the cycle by giving the plant as much light as possible until it can go outdoors again. It is not necessary to repot the bulb every year. Do so only if it has outgrown its pot.
Scott Aker is a horticulturist at the U.S. National Arboretum.