Q. My beautiful apricot colored tulips seem to be turning red after a few years in the ground. Is there anything I can do to prevent the bulbs from changing color?
A. It is important to understand that the original tulips, whose ancestral region is Turkey, look nothing like the Dutch tulips that we are accustomed to growing. By combining science and beauty, the Dutch bulb industry has created a spectacular range of hybrid tulips available for gardeners. However, it comes with a price.
It is not unusual for hybrids, such as tulips, lilies, irises and daffodils, to turn a different color, even after blooming its intended color for several years. Hybrids are bred to produce a single generation with particular characteristics, such as color or size. Yet, the same genetic nature of these characteristics that make them so unusual can also make them more unstable. Consequently, the variegation that we see in most plants is only "skin deep" and can be overcome by the plant's true characteristics such as color and size. There are some preventative measures that can delay reverting colors. Blooms are more likely to turn a different color when the plant is stressed, such as too warm a growing environment, over fertilization, improper water or soil pH, or a toxic reaction to an insecticide or other chemicals.
Q. I have nine spruce trees in my yard, all about 40 and 45 years old. Seven are seemingly healthy, but two have me concerned because there appears to be a lot of dying needles on the interior of the trees, and their color overall seems dull. These trees are alongside my driveway and receive more water than the others, though they have good drainage. They also receive a great amount of sunshine throughout the day. What could be affecting these trees? What do I need to do to bring them back?
A. It is normal for almost all evergreens to go through a shedding period every year in late summer and early fall. However, excessive needle loss may be caused by various needle diseases. Spruce mites cause devastating damage to the beautiful blue spruce and Colorado green spruce. Damage begins as dull green or browning interior needles as shown. Mites multiply by the thousands every 10 to 17 days. If conditions are favorable (cool, damp spring weather), they rapidly build throughout the summer.
The fungus Rhizosphaera kalkhoffii also can cause the spruce to lose needles. Infection occurs in the spring, usually on lower branches and works upward around the tree. Sometimes the disease may start higher and then work downward. Any size tree may be attacked, but small trees are more susceptible and are more likely to be killed by serious yearly infection. Infected foliage usually turns a mottled yellow in late summer on current-year needles. During the late winter and early spring, the needles turn brown and then fall off during the summer and fall, leaving current-year needles.
Because there are other noninfectious diseases that may mimic needle-cast symptoms, it is important to get positive identification of the disease. Take several branches to a reputable nursery or the University of Illinois Extension office at the Friendship Park Conservatory, 395 Algonquin Road, Des Plaines.
Q. Even though I don't overwater my compost, it is wet, soggy and sometimes smelly. What's causing this?
A. Three factors are usually to blame for smelly and slimy compost: Poor aeration, too much moisture or not enough nitrogen-rich material in the pile. A compost pile that is not turned regularly, while overburdened with materials, such as grass clippings and unshredded leaves, can become very dense when it is wet. This, in turn, prevents the center of the pile from receiving air, and you end up with a cold, soggy lump that just sits there. Aerobic bacteria -- the tiny microorganisms that make compost cook and decompose -- cannot live in such an oxygen-poor environment. Soggy compost is easy to fix. Begin by turning the pile and adding some "hot," nitrogen-rich ingredients, such as vegetable and fruit peels, coffee grounds, shredded corn cobs or sawdust. This should help get things cooking, and your pile should heat up within a few days. If continued wet weather is part of the problem, place a loosefitting tarp over the pile.
Q. I bought a new lilac bush last year. I planted it next to an existing lilac bush. It was in bloom last year when I bought it. This year it had no blooms, but looks very healthy otherwise. What could be wrong?
A. It was probably in bloom last year when you bought it because it was transported from a warm climate or greenhouse where it was forced to bloom. All plants must be physiologically mature before they are capable of blooming. During the juvenile stage of growth, plants are strictly vegetative and do not bloom. Most lilacs need three years to grow and develop, before they produce their first blooms. The bush could also be suffering from transplant shock. If you transplanted your lilac bush since the last blooming period, they sometimes will miss a year, as they need time to recover. Lilacs prefer full sun and well-drained soil. Without enough sunlight, the plant often will not bloom.
• Provided by Mary Boldan. Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines, open 9 a.m. to noon on Monday, Wednesday, Friday and Saturday. Call (847) 298-3502 or email Cookcountymg.firstname.lastname@example.org.