Flowering crabapple

About Flowering crabapple

Flowering crabapples are small trees grown for clouds of white, pink or red spring blossoms and small fruits that often hang on into winter. Bees and butterflies visit the flowers. Many older cultivars suffer from apple scab, fire blight and cedar-apple rust, so choosing a disease-resistant cultivar matters more than anything else.

Crabapples as a group grow in zones 3-9 (NC State) and do best where winters are cold and summers cool; humid summers bring more disease.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Plant container or balled-and-burlapped trees. Container trees can go in any time the ground can be worked, but fall is the best season in the South because roots keep growing through mild weather (Clemson). Dig the hole no deeper than the root ball and at least twice as wide, keep the top roots level with the soil, and mulch 2-4 inches without touching the trunk. Many are grafted: keep the graft union above the soil line (NC State).

Soil

Moist but well-drained, humus-rich, slightly acidic soil; adapts to many soils and handles drought once established (NC State, NDSU).

Test the soil first. Loosen a wide planting area and mix 10-20 percent compost into the native soil you dig out; don't use uncomposted bark, and don't dig deeper than the root ball (Clemson).

Feeding

• Spring to early summer, after the tree is established, and only if a soil test or pale leaves and weak twig growth show a need: slow-release nitrogen fertilizer with a ratio near 3-1-1 or 3-1-2 (3-0-1 or 3-0-2 if the soil test shows enough phosphorus). Spread it evenly from just outside the trunk flare to the dripline and water it in. Clemson cites 2-4 lb of slow-release nitrogen per 1,000 sq ft per year, split into a spring and a late-summer feeding; follow your soil test.

First-year watering matters far more than fertilizer: water daily for the first 1-2 weeks, every 2-3 days until week 12, then weekly, using about 1-1.5 gallons per inch of trunk diameter, until the tree is established, roughly 1.5 years per inch of trunk (UMN). Don't count on rain unless it was over an inch. Keep the graft union above the soil, and thin crowded branches so air moves through (NC State). Too much fertilizer can burn roots and push soft growth that pests and cold injure (Clemson).

Harvest

Blooms in spring, about late April-May (Purdue); no deadheading needed. Prune to thin dense, twiggy growth and open the crown to air (NC State).

Varieties (17)

Pests to watch for

Aphids, Japanese beetle, Twospotted spider mite, Roundheaded appletree borer, Annual cicadas (dog-day cicadas), Winter moth

Diseases and problems

Apple scab, Fire blight, Cedar apple rust, Powdery mildew, Frogeye leaf spot, Winter injury, Mechanical damage (mower, trimmer and tie wounds), Girdling roots

In the kitchen

Some crabapples make good jelly (NDSU), and the flowers are edible (NC State).

Safety: Like apple seeds, the seeds contain cyanogenic glycosides (ASPCA); don't eat seeds or chew stems and leaves.

Pets: Toxic to dogs, cats and horses (ASPCA 'Apple', which includes crabapples): stems, leaves and seeds contain cyanide, and wilting leaves are the most dangerous. Signs include brick-red gums, dilated pupils, hard breathing, panting and shock.