Spring with a cherry on top
By Adrian Higgins,
Gardeners are preoccupied with the weather because it affects what we do, but this spring has been so remarkably odd that the normal chat has risen to a new level of purpose.
The earlier a tree blooms at the start of the season, the greater the risk of calamity. Frost, rain, hail and wind can ruin the annual event in a few moments, so when my saucer magnolia tree opened the first week of March, three weeks early, I was sure its blooms would be wrecked. Instead, we had a long and glorious blossoming (the tree is 30 feet tall). The blooms coincided, strangely, with the flowering of the Japanese cherry trees. When the redbuds and dogwoods began to bloom as well, I thought I could expect just about anything. Except I was jolted on the last day of March, when a neighbor’s lilac tree bloomed.
Now that’s true March madness.
The Tidal Basin cherry trees may have bloomed early, but at least their precocious and fast-passing show was not cut short by freeze or gale.
The National Arboretum’s Margaret Pooler is in the business of trying to perfect the cherry, hybridizing as a way of improving flower color, or plant size and habit. She’s not that interested in developing a cherry tree that blooms for two weeks instead of one.
“Part of what makes flowering cherry trees so special is that their floral display is so brief,” said Pooler, who runs the arboretum’s cherry-breeding program. Pooler also knows that while she can control genes to some extent, she cannot direct the weather. Best not to be fixated on lengthening the bloom period. But she can work magic with the cherry blossom, as demonstrated in the release of a new hybrid named Helen Taft after the first lady who helped bring cherry trees to Washington a century ago.
The new tree is similar in size and habit to the iconic single-flowering Yoshino cherry, but the blooms are noticeably larger and more pink, growing more colorful in the center of the bloom as it ages.
One of its parents is the Yoshino cherry, actually grown as a cutting taken from one of the original trees planted in 1912 by Mrs. Taft and the Japanese ambassador’s wife, Viscountess Iwa Chinda. The other parent is the bell-flowered cherry tree, with large, pendent and deep pink blooms. Both trees bloom before the leaves form, making the flowers especially showy.
The new variety now enters the strange world of the wholesale and retail plant markets, which at once value novelty but are also extremely conservative. Growers and garden centers alike don’t like to devote time, money and resources into propagating and stocking trees that may not sell.
“It will probably be another five years” before Helen Taft is widely available to consumers, said Pooler.
The tree is the third in the cherry-breeding program since it began in the early 1980s. Pooler has a lot of genetic material to work with: The arboretum has one of the largest collections of Asian ornamental cherry trees in the world, including plants collected on trips to Japan decades ago.
Pooler has released two other cherry tree varieties in a program that is now more than 30 years old. (Propagating hundreds of crosses and then evaluating plants is a slow business.)
The first is one of my favorite cherry trees, named Dream Catcher. It is upright and vase-shaped, making it useful for spaces where the Yoshino, which can get 20 feet wide or more, won’t fit. Dream Catcher will grow to 25 feet high but just 15 feet across. The single blooms are larger than Yoshino’s and are a clear pink. The fall leaf color is lovely, a burnished orange.
It is a seedling of an Okame cherry and was among selections first evaluated by Pooler’s predecessor, the late Donald Egolf. The Okame cherry is a great garden plant itself, very upright and early blooming, though its abundant pink flowers are a little muddy to my eye.
The other arboretum introduction, released in 2003, is named First Lady, which is a cross between the Okame and the bell-flowered cherry. It is strongly upright, like Okame, and at maturity grows to 25 feet high and 14 feet across. The flowers, happily, look more like its bell-flowered parent, large and a dark rose pink.
Given the contributions to this stock by the bell-flowered cherry, you might wonder why this species isn’t more widely grown. Well, it is viewed as being somewhat tender, and a tree for the South. With our pattern of milder winters, I would consider it a pretty safe bet for the Washington garden.
Another good (and hardy) cherry not grown enough is the Sargent cherry, but this is a plant that needs some elbow room. It grows 40 feet high and as much across after several decades, and should be treated as a full-blown shade tree. The flowers are a clear medium pink and bloom with the apples, in a normal year. It has some of the bark ornament of the Amur cherry, famed for its coppery skin but a tree that dislikes our summer climate.
At the other end of the cherry scale from the Sargent cherry is a twiggy species named the Fuji cherry, Prunus incisa. It grows as a large shrub and would work well in a generous mixed border instead of, say, a viburnum or a doublefile or oakleaf hydrangea. The problem is in finding it.
Another useful diminutive cherry, the Kurile cherry, grows to just five feet, said Pooler, with showy, single pink blooms in early spring. “It’s a little bit smaller and more delicate” than the Fuji cherry, she said. The gene pool seems almost endless.
So many cherries, so little time.
Tip of the week Wait until after the spring flush of growth before trimming hedge plants such as hornbeams, boxwood, yew and privet. The new growth then can be removed, keeping the hedge at a constant size. — Adrian Higgins