Crepe myrtles are popular flowering shrubs and trees, known for their vibrant, long-lasting summer blooms. They add beauty to various landscapes with their diverse colors and forms. Propagating crepe myrtles involves creating new plants from existing ones, offering a cost-effective way to expand a garden or share desired varieties.
When to Propagate Crepe Myrtles
The timing for propagating crepe myrtles depends on the method. For cuttings, the growing season is suitable, with specific windows for different wood types. Softwood cuttings, from tender new growth, are collected in early to mid-summer (late May to mid-June). Semi-hardwood cuttings, more mature but flexible, are taken later (June through August). Hardwood cuttings, from dormant, woody stems, are taken in late fall or winter.
Crepe myrtle seeds are collected in late fall or winter, after flowers fade and seed pods turn dark brown and begin to crack open. This ensures the seeds inside are mature and viable. Store collected seeds in a cool, dry place until sowing. Planting seeds occurs in late winter or early spring, or even late spring in some regions, to give seedlings a head start before warmer weather.
Propagating from Cuttings
Choosing and Taking Cuttings
Selecting healthy parent material is an important step when propagating crepe myrtles from cuttings. Choose a branch free of disease, pests, or damage, as the quality of the cutting impacts its ability to root. Cuttings should be taken from new growth that is still pliable for softwood or semi-hardwood types. Softwood cuttings are green, tender stems 4 to 6 inches long. Semi-hardwood cuttings are 6 to 8 inches long, from stems that have begun to harden. Hardwood cuttings are 8 to 12 inches, taken from mature, woody stems when the tree is dormant.
Make a clean cut just below a leaf node, a swollen area where leaves emerge and roots are likely to form. Use sharp, clean pruning shears to prevent plant damage and disease. Ensure each cutting has at least three to four leaf nodes for rooting potential.
Preparing Cuttings for Rooting
After taking cuttings, remove all leaves from the bottom two-thirds of the stem, leaving a few at the tip. This reduces moisture loss and directs energy towards root development. Applying a rooting hormone can significantly aid root development. Dip the cut end into rooting hormone powder or gel, covering 1 to 3 inches of the base, then tap off excess.
A well-draining rooting medium is important. Suitable options include clean sand, perlite, or a blend of one part sand and one part peat moss. Fill a small container or pot, preferably with drainage holes, with the medium. Moisten the soil thoroughly before inserting the cuttings. Plant the cutting 1 to 4 inches deep into the moistened medium.
Rooting Environment and Care
Place the container in a spot with bright, indirect sunlight to provide energy without scorching. Direct sunlight can dry out the soil too quickly and harm the cuttings. Maintaining high humidity helps retain moisture and mimics ideal rooting conditions. Achieve this by covering the pot with a clear plastic bag or a propagation dome, ensuring the plastic does not touch the cutting.
Consistent moisture is important; the soil should remain damp but not waterlogged to prevent rot. Regularly check moisture levels and mist the cuttings or soil as needed. Providing bottom heat, such as with a seed starting heat mat, can promote faster rooting, with a temperature range of 70-85°F (21-29°C). Roots begin to form within four to eight weeks. Signs of successful rooting include new leaf growth or resistance when gently tugging on the cutting.
Propagating from Seed
Crepe myrtles can be grown from seed, though this method may not produce plants identical to the parent due to genetic variability. Collect seeds from dry, cracked pods, gently shaking them over a bowl to release the seeds. Store dried seeds in a cool, dry, dark location until planting in late winter or early spring.
To sow, fill pots or seed trays with a light, well-draining seed starting mix. Press seeds lightly onto the surface of moist soil; crepe myrtle seeds often require light for germination, so avoid deep burying. Cover pots with a plastic bag or dome for humidity and place in a warm location (around 75°F / 24°C) with bright, indirect light. Germination occurs within two to four weeks, though it can take over 30 days.
Caring for New Crepe Myrtle Plants
Once cuttings have rooted or seeds have germinated into small seedlings, they require care. If using a plastic covering, remove it once roots are established or seedlings emerge. Gradually acclimate young plants to outdoor conditions over about two weeks, a process called hardening off. This involves exposing them to increasing periods of sunlight and outdoor temperatures.
When plants are large enough, transplant them into larger pots or directly into the garden. Choose a location that receives at least six hours of direct sunlight daily, as crepe myrtles flourish in full sun. Water newly transplanted plants deeply and consistently, especially during their first growing season. While established plants are drought-tolerant, consistent moisture supports healthy growth. Monitor for pests or diseases and address issues promptly to protect young plants.
Tips for Successful Propagation
Cleanliness is important in plant propagation. Always use sharp and sterilized tools, such as pruning shears, to prevent the spread of disease. Ensuring good drainage in your propagation containers and rooting medium is also important. Excess water can lead to fungal issues and rot, hindering root development.
Maintaining consistent environmental conditions, including temperature, humidity, and moisture levels, improves success. Significant fluctuations can stress young plants and impede rooting or germination. Rooting and germination times can vary depending on conditions and the specific plant. Regularly monitor your cuttings and seedlings for signs of growth or issues.