Q I planted a Chinese fringe tree as the centerpiece of my garden five years ago. It is now eight feet high but has not bloomed, except for one slight flowering the first year. It receives full sun and has been watered during droughts and fed slightly. Everything else in the border is thriving.
I planted a Japanese clethra at the same time. It is in partial shade and is watered in periods of drought. It is almost six feet tall and beautiful in foliage but also has never bloomed. How do I get these plants to flower?
A Your Chinese fringe tree may need another year or two before it reaches blooming size, and there is something else to consider. The Chinese fringe tree, Chionanthus retusus, is an odd species in that there are two distinct races. One race has nearly oval leaves, tends to branch near the base of the trunk and grows as wide as it does tall at maturity. It also blooms precociously and heavily. The other race has long, pointed leaves that are typically larger. This version is more upright than spreading at maturity and is more hesitant to bloom. While both are lovely, I much prefer the oval-leaved race.
There is a case for buying a Chinese fringe tree in leaf season, so you know which kind you are getting.
If your plant has pointed leaves, it will bloom when it is ready. You may be able to stimulate blooming by slicing through some of the roots in early spring to interrupt rampant vegetative growth.
Your Japanese clethra may need more light to bloom profusely. It is still young enough to move it to a sunnier spot, which is best done soon, before the shrub breaks dormancy. Be careful not to water or fertilize it too frequently.
I am having serious problems with shrubs in a small Georgetown garden. In one corner of the fenced yard stands a holly tree. On either side of it I've tried to plant a row of euonymus running along the fence. Two successive plantings have died. The leaves became pale and dried out. Eventually, the stems died. I planted variegated boxwood in the same spot. Now the same thing is happening. The leaves are browning despite plenty of watering.
It is conceivable that your fence was treated with creosote and its fumes are killing the leaves, but I think your shrubs are drowning. While holly is quite tolerant of saturated soil conditions, euonymus and boxwood are not. Check the soil immediately after a period of prolonged rainfall. If water appears in a hole that you dig near the holly, and remains in the hole for more than a day, you are dealing with a periodically saturated soil that will limit what you can grow. If not, you may try digging up the boxwood, adding some soil to the bottom of their holes, and setting them back. Boxwood have surface roots that must be kept free from waterlogging, and it is better to set them a little too high than too low. Give them a thin layer of mulch, which should be kept away from the crown of the shrub.
If the problem is chronically wet soil, you may be able to grow Japanese plum yew or bayberry in that location.
I planted several specimens of heaths and heathers in 2003. They came through last winter but five of them gradually turned brown and died. The soil is clay, amended with leaf mulch. The plants were adequately watered, not over-watered, and given a mulch. How do you keep them growing?
Both of these plants are very difficult to grow in soil that contains much clay. They need acidic soil conditions and cannot tolerate even brief periods of soil saturation. On the other hand, the roots must never dry out. To make matters worse, they don't like summer heat, particularly if night temperatures are routinely above 60 degrees. They are not easy plants to grow in our area.
If you are brave enough to select the challenges they present, you might try growing them in a raised bed that is composed of two parts sand mixed with one part pine fines or peat moss. Mulch them with pine needles and water them if the soil becomes dry.
If you don't want to battle your soil conditions, you may want to settle for Mexican heather, Cuphea hyssopifolia. While it isn't hardy in our area, it fulfills the same function in the landscape and will bloom throughout the growing season.
Scott Aker is a horticulturist at the U.S. National Arboretum.
