Bald cypress

About Bald cypress

Bald cypress is a native conifer of Southern swamps that loses its soft, feathery needles each winter after they turn orange to cinnamon-brown. It grows in standing water, where it forms knobby 'knees', yet does fine in ordinary yard soil, and it is among the longest-lived trees in the world.

Zones 4-9 (NC State); it yellows (chlorosis) in alkaline soil.

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. Knees form mostly when it grows in or near water (NC State).

Soil

Acidic soil of almost any texture, wet to well-drained; tolerates standing water and long flooding, but leaves yellow in alkaline soil (NC State).

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.
• Late summer to early fall, the second half of the year's split feeding (only if a soil test calls for it): slow-release nitrogen fertilizer, same as spring. Apply the rest of the year's amount over the root zone and water in. Don't feed a drought-stressed tree in summer (Clemson).

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. Alkaline soil causes yellowing (chlorosis); test pH before planting. It can take wet soil and even standing water (NC State). Too much fertilizer can burn roots and push soft growth that pests and cold injure (Clemson).

Varieties (9)

NC State documents these; several are dwarf or weeping forms.

Pests to watch for

Bagworm, Twospotted spider mite

Diseases and problems

Twig blight, Iron chlorosis

In the kitchen

Pets: Not on the ASPCA's toxic plant list for dogs.