Collect seeds from the five-valved capsules, up to 5 inches long, that fall in midwinter from the mahogany tree. Seed propagation is the preferred method, states Texas A&M horticulture professor Fred T. Davis, although cuttings offer benefits of providing cloned trees for research.
Remove the winged seeds from sections of the capsule for prompt planting.
Plant seeds in a plug flat system with exceptionally deep cells containing a sterile seed-starting mix. Break the seed wing to speed germination and place the seed at a depth twice its thickness. Seeds do not require soaking or other treatment before germination.
Take cuttings from a mahogany branch with pruning shears far enough down a cutting representing older growth.
Trim the cutting to 4 to 8 inches, keeping four to five leaves on the top.
Treat the cuttings with rooting hormone and set them in a rooting medium, such as a mix of sand, perlite and peat, in a small pot or repurposed milk carton. Regularly mist the cuttings with a spray bottle to maintain the humidity in the air around them.
Place them in a larger container or garden bed for a year to mature before setting them in a permanent location.