Q: I want to plant a small flowering tree in a sunny spot in my garden. There are already dogwoods, cherries, plums and redbuds in my neighborhood. Can you suggest a few spring-blooming alternatives?

A: Even if you are in the mood for something unusual, you don’t have to resort to the exotic. There are several underused American natives that fit your request. They may not match the vividness of familiar Asian species in full bloom, such as the frilly double-flowered Kanzan cherry, but their quiet beauty will draw many admirers. And most will grow no more than 30 feet high, the textbook definition of a small garden tree.

One of the most graceful, Carolina silverbell (Halesia tetraptera), has dangling hoop skirts of pure white flowers followed by lobed fruit. In Dirr’s Hardy Trees and Shrubs: An Illustrated Encyclopedia, Michael Dirr, a woody-plant expert, praises its merits: “The flowers, in a subtle, not boisterous way, are among the most beautiful of all flowering trees.”

Other Halesia varieties that may do the trick include Rosea, a pink form, and Variegata, which sports white flowers and variegated leaves. A shorter variety, Wedding Bells, has large white flowers and reaches 20 feet.

Another good candidate is the serviceberry (Amelanchier), a white-flowered shrub-like tree with several useful varieties. They include the elegant Allegheny serviceberry, which blossoms into a cloud of white and looks at home in either a woodland or a small garden. According to folklore, the serviceberry got its name from 19th-century settlers heading West who knew that when the tree was in bloom, the ground had thawed, so it was time to dig graves and bury those who had died during the winter.

For a dramatic statement in the garden, the fringe tree (Chionanthus virginicus) is sculptural even when not in bloom, thanks to its graceful, often-multiple trunks. In the later part of the season, in May and June, it produces a spectacle, covering its twisting branches with a fragrant thread-like bunting of delicate white flowers.

The Eastern redbud (Cercis canadensis) may not interest you because of its ubiquity, but consider its white variety, Alba, or Forest Pansy, a darling of plant aficionados several years ago, which has pink blossoms and dark purple leaves. A new, harder-to-find variety, Hearts of Gold, has vivid yellow foliage that leafs out after the decline of its hot pink flowers.

If you must have something exotic, though, consider two non-native trees: the Japanese snowbell and the yellowhorn from China. The snowbell (Styrax japonicus) resembles a Halesia and, like other light-colored flowering plants, looks best against a backdrop like a solid wall or a dark hedge. The yellowhorn (Xanthoceras sorbifolium) has shiny dissected leaves and scented white crepe-like flowers with yellow and red centers. It is relatively rare but worth the trouble to find.

Lilacs, peonies like wood ash

Q. We have wood fires three to four times a week and accumulate a lot of ash. Can I use it in my compost pile or anywhere in the back yard?

A. You can use it in the garden as long as the wood was not treated with any chemical preservative. Wood ash is strongly alkaline and may slow microbial action, so don’t add it to your compost heap. Wood ash contains significant amounts of potassium, so it is a beneficial fertilizer. It also contains calcium carbonate, which is the predominant compound in lime, and will help to increase soil pH. Certain plants, such as peonies and lilacs, benefit from this increase in pH if your soil is acidic. Conversely, wood ash should not be spread around azaleas or other plants that grow well only in acidic soil. And don’t use wood ashes where you plan to grow potatoes, because it can raise the pH sufficiently to favor a disease called scab on the tubers.

Reluctant viburnum

Q. I have two doublefile viburnums planted next to each other. For the past three years, one has failed to bloom while the other blooms faithfully every spring despite drought and neglect. How do I coax its companion into flowering?

A. You may believe the two are identical varieties, but they might be different even if they were labeled the same at the nursery. The botanical name for the doublefile viburnum is Viburnum plicatum tomentosum. Unlike its parent species, the botanical variety tomentosum has a ring of showy sterile flowers surrounding a cluster of far smaller fertile flowers that are capable of developing into fruit. Tomentosum blooms two to three weeks earlier than the straight species. And when it blooms, V. plicatum has only sterile flowers. Even if you do have tomentosum, there are several different cultivated varieties of it. These differ in habit and also at what age they begin to bloom. It’s conceivable that your nonbloomer simply hasn’t reached flowering maturity yet.

If the plants are genetically identical, equally healthy and the same age, I’m at a loss as to why one would bloom but not the other. Like many shrubs, overly vigorous growth in viburnums may suppress flowering. Do some root pruning in the spring to see if you can check its growth and stimulate flowering.

Use a sharp shovel to cut some of the roots just inside the drip line, creating a sort of dotted line around the circumference of the shrub. This may spur blooming the following spring.

Move tomatoes every year

Q. I read about using repellents on tomatoes, namely hot pepper wax and blood meal, to keep rodents from eating them as they turn red. Will these products affect the taste of the tomatoes? Also, my tomato plants were afflicted with fungal disease last year, and I wonder if it will carry over in the soil for this year’s crop.

A. In spite of its name, hot pepper wax doesn’t have an odor or flavor. Blood meal does have an odor, but it won’t permeate the fruit, and if some is lying on the fruit at harvest time, it can be easily washed off.

Tomato diseases are notorious for lingering year to year in the soil. In commercial production, growers allow fields to lie fallow or plant unrelated crops for four or five years before planting tomatoes in the same ground. In areas where land is at a premium, soil is sometimes fumigated or solarized so tomatoes may be grown year after year.

If possible, move tomatoes every year. You can even incorporate them in a perennial garden or flower beds for a few years. Large containers are another option. Don’t grow other crops in the nightshade family in your tomato beds. Peppers, eggplant, ground cherries, tomatillos and potatoes are subject to many of the same diseases as tomatoes and will allow them to persist.

In recent years, heavy spring rains have played a major role in all the disease problems we have seen. In many years, it is better to wait to plant tomatoes until early June when drier, hotter weather arrives and diseases are less likely to be severe. Fruits that grow in the warm, dry sunny days and cool nights of autumn develop far more flavor than the midsummer crop.

Compiled from New York Times and Washington Post reports.