Black Alder Propagation

Cuttings

• The University of Florida Extension recommends using softwood cuttings to propagate black alder. Take the cuttings after the first frost in fall. Use sharp scissors to cut 4- to 8-inch-long sections from softwood stems, measuring from stem tips. Remove all the leaves from the lower half of each cutting. You do not have to angle the cut at the stem base in deciduous plants like black alder.

Seed

• To propogate with seed, collect the seed from black alder during fall and stratify in a cool place until summer. To stratify, mix together equal amounts of sand and peat in a small container and moisten it with a little water. Mix the black alder seed in the medium and place it in the fridge at 40 degrees Fahrenheit. Keep the medium moist throughout the stratification period. Even with stratification, the seeds of holly are very slow to germinate.

Planting

• Fill a medium sized pot with a rooting medium of equal amounts of sand, peat and perlite. Dip the black alder cutting in the rooting hormone IBA TALC 8000 PPM, as recommended by the University of Florida Extension. Plant immediately in the pot. Place in a bright, warm spot out of direct sun with the temperature of 72 to 75 degrees Fahrenheit, and mist the cuttings regularly. It takes anywhere between four to six weeks for the cuttings to root. Sow seeds in summer and soak overnight in warm water prior to planting. Let seedlings or rooted cuttings grow stronger before moving to a permanent spot in the garden.

Cultural Requirements

• Although black alder adapts well to areas of full to partial sun, the plant flowers and produces fruit more prolifically in areas of sun. Make sure soil is slightly acidic, moist and fertile. The shrub does not thrive in alkaline or neutral soil, and is intolerant of drought, requiring regular irrigation. A pollinator or male plant is required for good pollination. Black alder is hardy in USDA zones 3 to 9.