Joe’s Journal: Spring Edition – Spring Flowering Trees & Shrubs
Welcome to spring! We’re going to spend the next 3 months exploring new seasonal subjects, starting with a guide to blossoming trees and shrubs. Keep checking in for more landscape, garden, and tree knowledge!
The preponderance of spring flowering trees and shrubs in our landscapes are from China, Japan or eastern Europe. All flower buds were formed in the previous growing year. Keep this in mind when pruning or thinning branches particularly after mid-summer, when floral buds have set. Trees and shrubs that have pre-formed floral buds may be considered for forcing in winter indoors as cut flowers. In general, take cuttings after the plants have had at least an 8-week cold period (3rd week in February). The single native tree in this entry is the Eastern redbud. The other trees and shrubs listed here are non-natives, but are widely planted and common in our landscapes. A few have become naturalized, and in some places are invasive. Plum, pear, cherry and quince are all in the rose family (Rosaceae) and therefore share many of the same growing requirements and susceptibility to pests and diseases. Plant these in full sun, in well-drained soils. Prune after flowering to keep the canopy open. This allows for good air circulation to reduce disease incidence, particularly in wetter regions. After a long winter, what follow are the early harbingers of spring:
Purple-leaved Flowering Plum or Cherry Plum (Prunus cerasifera ‘Atropurpurpea’) is one of the earliest trees to bloom in late winter – early spring. In Japan, it is called Winter cherry. A small flowering tree, it will growth 15 to 25’ in height, and about as much in width. Often planted in the landscape as a specimen tree for its fragrant blossoms and purple leaves. Best grown in full sun.
Star Magnolia (Magnolia stellata) blooms in late winter to very early spring. It produces star-shaped fragrant white or pink flowers. Blooms for several weeks in spring, if not hit by frost, which will kill the opened flowers. It is a small tree or multiple-stemmed shrub growing 10 to 20’ in height and 10 to 15’ in girth. Best grown with ample organic matter in partial shade to full sun.
Forsythia (Forsythia spp.) produces a profusion of yellow flowers in early spring. There are hybrids (Forsythia x intermedia) and varietals available including F. x intermedia and F. viridissima ‘Bronxensis’. The latter was derived from a seedling grown at the New York Botanical Garden. It is a low growing ground cover, unique among its cohorts! Forsythia tolerates urban conditions well. Best grown in full sun for best floral display. Prune after flowering, but before mid-summer. Late season clipping will remove much of the next seasons flower buds. The plant is relatively disease free, and for that reason is perhaps overly planted. Winter temperature blow -5F could cause floral bud kill, reducing the early spring display. Periodically remove the oldest stems to keep the plant productive. It lends itself to mass plantings and informal border hedges.
Saucer Magnolia (Magnolia x soulangeana) is a hybrid magnolia that blooms a week or so later than Star magnolia. Like Star magnolia, it prefers soils rich in organic matter, but likewise susceptible to bud kill when temperatures fall below 25 F. Flowers can be white, pink or purple/lavender. Multi-stemmed plants grow from 15 to 30’ in height and 15 to 25’ in width. It is often planted as a specimen or in a mixed planting. Trees are susceptible to soft scale. Look out for sooty mold (blackened stems), which are indicative of magnolia scale infestation.
Callery Pear (Pyrus calleryana) was first introduced as street tree because it tolerates urban conditions, is relatively small (therefore could be planted under power lines), produces a profusion of white flowers early in spring, has small, almost negligent fruit, and has leathery green foliage that turns purplish bronze in the fall. Almost the perfect tree! Except for a number of significant faults that ultimately detract from its positive attributes. It has a decurrent habit, meaning that it produces a number of competing leaders (stems). These grow at an acute angle that prevents the leads from knitting together. It is weak wooded and in just 10-20 years the trees break apart. Wind, ice, and snow are contributing factors in their early demise. Corrective pruning to eliminate future breakage has to be done early in the life of the tree, and ought to start in the nursery. It is widely planted, and arguably, overplanted in the landscape. Moreover, in the mid-Atlantic, these non-native trees are invading woodlands. Some states are banning the planting of Callery pear. The trees can potentially spread fireblight to other rose family plants. For these reasons, it is best to avoid planting these trees.
Weeping Higan cherry (Prunus x subhirtella ‘Pendula’) produces single or double light pink flowers in early spring that last about a week. The tree is pendulous in form, and grows anywhere from 15 to 40’ in height and 15 to 25’ in girth. Fall color is yellow. Cherry trees are in the Roseaceae (rose family) therefore are susceptible to a number of diseases and insect pests affecting the family including powdery mildew, fireblight, black knot, root rot, cankers, aphids, scales, defoliating caterpillars and Japanese beetles. Plant as a specimen tree in well-drained soil in a location that receives full sun.
Flowering Quince (Chaenomeles speciosa) blooms profusely scarlet-red in spring. Flowering quince produces edible fruit, which are made into preserves. The shrub will grow from 4 to 6’ in height with arching stems, and though it will tolerate some shade, it is best growth is in full sun. It spreads by suckers, which may be a source of new plants should you wish to propagate them! Floral buds are set on the previous seasons wood, so prune plants after flowering. Use as the quintessential (!) specimen or simply plant as an informal hedge.
Eastern Redbud (Cercis canadensis) is a small flowering native tree, 20 to 30 feet in height and girth, producing pink to lavender pea-like flowers in early spring. A member of the legume family, it produces inedible brown pods after flowering. It is a great tree to plant to attract wildlife: flowers attract pollinating bees and hummingbirds and the pods are food for song birds. Plant as an understory tree at a wooded edge along with flowering dogwood (Cornus florida), as it will do well in partial shade. Alternatively, plant as a specimen tree in the landscape or in a mixed perennial bed.
PJM Rhododendron (Rhododendron ‘PJM’), a hybrid rhododendron, produces compact trusses of lavender flowers, early in spring. The plant grows from 3 to 6 feet high and just as wide. The foliage is fine textured and evergreen, turning bronze-purple in winter. A member of the Heath (Ericaceae) family, it is related to blueberries, cranberries, wintergreen, and azaleas. Plant in partial shade and in acidic soils rich in organic matter. They are shallow-rooted, growing best in moist but well-drained soils. They benefit from a mulch of woodchips or pine straw. PJM Rhododendrons lend themselves to mass plantings, naturalized landscape plantings and as specimen plants.
~ Signing off for now, Joe