An acacia tree is commonly propagated from acacia seeds, as well as cuttings. Seed propagation is generally considered the easiest and quickest method of propagation. The acacia tree has over 1000 species native to many warm temperate or tropical regions of the Americas, Europe, Asia, Africa and Australia. Besides producing many different shades of yellow blooms (a few species produce purple or red blooms), the acacia tree has been valued for its timber, edible seeds, and medicinal uses for thousands of years. When planting an acacia from seed, follow these guidelines for best results.
Preparing Acacia Seeds
The seed coat of the acacia is hard; if you just throw it in the ground, germination could take many months or not occur at all. First, test your seeds to see which ones are the best. Place in a pot of cold water. Keep the sinkers; throw out the floaters. Two common ways of softening the seed coat and speeding up germination is by piercing or scraping the seed coat by hand and/or soaking in near boiling water for 24 hours. If doing both, nick the seed coat first, then soak. If you are working with a large number of seeds, rub handfuls of them together between two pieces of sandpaper. If you have fewer numbers, use a needle or file to scrape or pierce the seed coat away from the seed stalk. Be sure not to damage the soft part of the seed coat. After soaking, the seeds should swell to about twice the original size.
Germinating Acacia Seeds
Sow seeds about 1/4 inch apart in a seed tray. Using a prepared seed mix may be helpful. Or you can make your own, mixing 3 parts river sand and 1 part peat moss, pine bark or vermiculite. Cover the seeds lightly with soil (about the depth of a seed), lightly press down the soil and water. Place above ground level in a warm, humid, partly-shaded area. Using a propagator is helpful, but not necessary. Keep the soil moist but not wet. Misting frequently will help keep you from overwatering. Germination should occur between several days to a month.
Transplanting Acacia Seedlings
Seedling are ready to be planted in their own container when they reach about 1 inch tall. Plant in a pot about 3 inches wide using a general well-draining potting soil, or your own mix of garden soil and compost. Press the soil down around the container, and slowly introduce seedlings to sunlight by first placing near a window for only a couple hours for a week or, and then, if warm enough, placing outside for a couple of hours of morning sunlight a day.
Transplanting to the Yard
Because the acacia quickly develops a long root system, transplant outdoors whenever the temperature is consistently over 65 degrees F. Plant to its original depth and spread with mulch. Water whenever the water is dry, being careful not to overwater. Acacias do best in somewhat dry conditions. If fertilizing, use a low-nitrogen fertilizer, like a standard bonzai fertilizer. This will encourage it to bloom to its full potential.
Enjoy the beautiful yellow blooms of the acacia tree!