the little trees of spring
From the Davis Enterprise, February 26, 2004
One of the pleasures of living in Northern California is that we have the best of both worlds--we can grow many of the subtropicals that make California a special place, but we get enough winter chill to grow the spring flowering shrubs and trees. The almond blossoms you see along the freeway and in Capay Valley mark the beginning of spring in the Sacramento Valley. Folks in other parts of the country are often trading blizzard stories when I mention this (the most common reply: 'almonds grow on trees?').
Many of these small deciduous trees are flowering relatives of our familiar fruit trees. They provide bursts of showy flowers, from the almonds and plums in February, through the crabapples, pears, cherries, and magnolias in March and April, and into the summer with the pomegranates. Some fruit producing trees are showy enough to qualify--'Red Baron' peach produces vivid red flowers and high quality fruit.
Showy ornamentals in the summer include the Crape myrtle and Rose of Sharon (Hibiscus syriacus). One small tree can be a real focal point, or a group can provide a brief but spectacular display. Your big shade trees provide background and ambiance, while these smaller trees are at what designers call 'human scale'. Most of these trees grow to 15 - 25' tall, with varying spread, and can easily be kept to no more than 15' with one annual pruning.
The choices vary regionally, and while some of that is climate-related (Crape myrtle needs heat, for example), a lot of it is just a matter of preference and history. Flowering cherries are traditional in the warmer parts of the east, and dogwoods are very common there and in the Pacific Northwest. Dogwoods don't grow in Davis due to our water. Crabapples grow fine here but seem to be rarely planted; they are very popular in Oregon. The red-leaf flowering plum (Prunus 'Krauter Vesuvius') has become ubiquitous in wine country and is among the most commonly planted trees in new subdivisions here.
Mostly in three species of the genus Prunus, are much loved but fussy. They were widely planted in west Davis (Burr St. once had them as street trees), but are mostly gone because they need excellent drainage and are susceptible to sunburn and borers on the trunk. Paint the trunk with interior white latex and prune as little as possible, and never plant them in a lawn.
There are many varieties of Prunus serrulata. Kwanzan is especially showy, with large double pink flowers and a vase-shaped habit. Mt. Fuji is white. Prunus subhirtella varieties are very graceful weeping trees with pale pink flowers in great profusion. Give them room--20 across! Prunus yedoensis 'Akebono' has a spreading and slightly weeping habit, with billows of soft pink, double flowers.
... are species and hybrids in the genus Malus, same as our eating apples. They have a similar range of growth habits and bloom color as the cherries, but are much less fussy about heavy soil. They will even take lawn watering, and don't mind our hot dry climate. Upright, spreading, or weeping, and in shades of pink, white, or red. Most produce fruit, some of which is showy and certain varieties can be used for jam.
Varieties should be selected for resistance to fireblight, as it is a common and virulent bacterial disease here. Hawthorn trees (Crataegus) are similar to crabapples, but are very uncommon in the nursery trade, perhaps because fireblight is a major problem.
... are not thrilled about our heavy soil and hard water, and prefer protection from the hottest sun--but they are well worth the effort for their late winter show of tulip-like flowers (the other tree called Tulip tree is Liriodendron tulipifera). Find a spot where they will be watered deeply once a week and shaded (at least their roots) from the west; amend the soil in an area 3 - 4' across, and add some pH adjuster. Breeders have produced a number of hybrids with incredibly showy flowers in white, pink, magenta, and (rarely) pale yellow.
The star magnolias (M. stellata) are the smallest, to about 10', with many-petalled white blooms. M. soulangeana varieties, the saucer magnolias, are the showy ones you'll see blooming here and there around town next week--but they have become uncommon in the trade in favor of the new hybrids (for pictures and info about these, visit our web site at www.redwoodbarn.com).
Among the first to bloom, right with the almonds, the Pyrus species are worth mentioning because they are so widely planted. The earliest, with the dirty-ish white blooms, is Pyrus kawakami, a small, spreading tree used for espaliers and in patios. Very prone to leaf spot fungus and fireblight disease, so it is not recommended, though interestingly these diseases don't seem to weaken the trees. There are a number of specimens in downtown Davis and they look fine after the spring disease season passes.
The large upright growers, with masses of pure white blooms (that smell like socks), are forms of Pyrus calleryana. Very widely planted for a couple of decades, the problems have become obvious to tree professionals. Calleryana pears are not recommended due to poor branch structure, susceptibility to fireblight and mistletoe, and the fact that they are becoming invasive in rainier climates. There are several varieties (Bradford, Aristocrat, Chanticleer, Capitol) but none are recommended any more.
Prunus cerasifera, P. blireiana, and P. cistena are the most common spring-flowering trees in the area, with soft pink blooms in late February and early March. Old forms had annoying, copious fruit, but Prunus 'Krauter Vesuvius' is nearly fruitless and has vivid purple-red foliage. For similar foliage and flowers, but on a shrub, plant Prunus cistena. Prunus blireiana is entirely without fruit, with foliage that changes from burgundy in the spring to dark green in summer. 'Purple Pony' is a small cultivar that tops out at about 10 to 12 feet all with 8 to 12 foot spread. Purple Pony is entirely fruitless.
Cercis species all have magenta flowers and attractive foliage, but the two common species are very different in their habits and requirements. Western redbud (C. occidentalis) is the spectacular shrubby species planted all down the west end of the Arboretum--worth a visit anytime from late March into early April. It usually grows as a large shrub, okay with full sun but the foliage looks best in summer with light shade. Western redbud must be dry during the summer as it is especially susceptible to crown and root rot. I have also seen branch dieback on it. Plant it with other natives or Mediterranean plants, and water only every few weeks at the most.
Eastern redbud (C. canadensis) is never drought-tolerant (even accepting lawn watering), grows naturally as a tree, and prefers shade from the hot afternoon sun here.
'Oklahoma' is a hybrid of the eastern species that is much more heat-tolerant, and is also tolerant of irrigation, so it is a better choice for most gardens.
These are the trees that mark the seasons for us with their brief but spectacular blooms. Choose a focal point--visible from the kitchen, out a window, or along the street--and combine them with spring bulbs and summer-flowering perennials. Be sure to send your eastern family and friends pictures to enjoy while they're still huddling by the fire with their seed catalogues, waiting for spring!
See also Small trees
© 2008 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616
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