When I landscaped my yard a few years ago, I chose trees that I thought would give me fall color. But they’ve been a disappointment. Does good fall color happen only on mature trees?
The ability to produce brilliant fall color is based on a tree’s genetics, not its age. Some species and cultivars are better than others at producing the pigments that light up autumn.
In addition, climate and weather play a big role. Sunny fall days and cold (but not freezing) nights encourage sugar production and retention in the leaves, which in turn promote more of the red and purple pigments known as anthocyanins. Some regions, such as New England, have a color-promoting climate. The same species can display different amounts of color in different regions.
But sometimes weather spoils the show. Summer drought or excessive autumn heat decreases pigment formation. A hard freeze in early fall can turn leaves directly from green to brown. Because temperatures and rainfall vary from year to year, no two falls are identical.
The best way to select trees for fall color is to look around your community in a typical fall and see which trees are the most colorful. Or check regional sources of information, such as your state’s cooperative extension office. —Doug Hall
The plant names written in Latin are so confusing. Why don’t you just call everything by its regular English name?
There are several good reasons for using botanical nomenclature when identifying plants. For one, scientific names are an international language, so each species of plant (or other living creature) is identified by the same name throughout the world. Scientific names also reveal relationships among plants by grouping those with similar characteristics and evolutionary paths into the same order, family, or genus. The two-word name given to a species, such as Vinca minor or Ginkgo biloba, is called a binomial or scientific name. It’s often written in italics with the first of the two words capitalized.
In contrast, common names of plants can be imprecise. “Snowball bush” can refer to several types of viburnum or hydrangea; “bluebell” can be the English bulb of meadows, the wildflower of North American woodlands, or any of several summer-blooming perennials. The plant I call beebalm (Monarda didyma) you may know as Oswego tea or wild bergamot.
There’s nothing wrong with using common names, but knowing the scientific name of a plant will help you to search for more information about it online or to find a retailer that sells it. If you are unsure of how to pronounce those Latinized names, do what a botany professor told me years ago: Whether you know the correct pronunciation or not, always say scientific names in a strong and authoritative voice, and everyone else will think they’ve been saying them wrong. —Doug Hall
There was a hard frost last night that killed the dahlia tops. I’m going out of town and won’t have a chance to dig up the roots for at least a week. Is that too late to save them?
For the tuberous roots of dahlias to be damaged, the soil would have to freeze several inches deep — something that usually doesn’t happen until a month or two after the first frost. (In USDA Plant Hardiness Zones 8 and warmer, it may not happen at all.) So you can delay this task a few weeks without worry.
Here’s my technique for storing tender bulbs, including dahlias and cannas, through the winter. Caladiums, tuberous begonias, elephant ears, and gladiolus prefer a slightly warmer storage temperature of around 50°F. —Doug Hall