The Florist Guide to Flower Propagation Methods

Growing flowers successfully starts with choosing the right propagation method for each species. Different flowers have evolved various reproductive strategies, and understanding these can help you achieve better germination rates, healthier plants, and more blooms in your garden.

Flowers Best Grown from Seed

Annual Flowers

Most annual flowers are ideally grown from seed because they complete their entire life cycle in one growing season and naturally produce abundant, viable seeds.

Sunflowers are among the easiest flowers to grow from seed. Their large seeds have high germination rates and can be directly sown in the garden after the last frost. The taproot system makes transplanting difficult, so direct seeding is preferred.

Zinnias germinate quickly and reliably from seed, usually within 5-7 days in warm soil. They're heat-loving annuals that don't transplant well once established, making direct seeding the best approach.

Marigolds produce abundant seeds and germinate easily. French marigolds can be started indoors 4-6 weeks before the last frost, while African marigolds benefit from an earlier start due to their longer growing season.

Cosmos have feathery seeds that germinate readily in poor soil conditions. They actually prefer not to be overfed, making them perfect for direct seeding in less-than-ideal garden spots.

Morning Glories have hard seed coats that benefit from scarification (nicking with a file) or soaking overnight before planting. Their vigorous growth habit makes them unsuitable for cutting propagation.

Perennial Flowers

Many perennials can be grown from seed, though they often take longer to establish than annuals.

Rudbeckia (Black-eyed Susan) seeds need cold stratification to break dormancy. Sow seeds in fall for spring germination, or artificially stratify by storing seeds in moist sand in the refrigerator for 6-8 weeks.

Echinacea (Purple Coneflower) seeds also require cold treatment. Fresh seeds have the highest germination rates, so collect them in late fall and either plant immediately or store properly for spring sowing.

Lupines have hard seeds that need scarification and cool, moist conditions for germination. They develop deep taproots that make transplanting challenging, so direct seeding is recommended.

Columbines produce tiny seeds that need light to germinate and benefit from cold stratification. They readily self-seed in the garden once established.

Why Seeds Work Best

Seeds are the preferred method for these flowers because they either have taproots that don't transplant well, produce seeds with high viability, or have evolved specific germination requirements that make sexual reproduction more reliable than vegetative propagation.

Flowers Best Grown from Cuttings

Tender Perennials and Annuals

Many flowers that are treated as annuals in cooler climates are actually tender perennials that root easily from cuttings.

Coleus is one of the easiest plants to propagate from cuttings. Stem cuttings root in water within a week, making it simple to overwinter plants indoors or create new plants from favorites.

Impatiens (both standard and New Guinea types) root readily from tip cuttings placed in water or moist potting mix. This method preserves exact colors and patterns that might not come true from seed.

Begonias can be propagated from stem cuttings, leaf cuttings, or even leaf sections. Wax begonias root easily from 3-4 inch stem cuttings, while rex begonias can be grown from leaf cuttings with the veins cut and placed on moist soil.

Geraniums (Pelargoniums) are traditionally propagated from cuttings to maintain cultivar characteristics. Take cuttings in late summer for overwintering indoors, allowing cut ends to callus for 24 hours before planting.

Hardy Perennials

Many perennial flowers can be propagated from cuttings, especially when you want to preserve specific cultivars.

Chrysanthemums are typically grown from tip cuttings taken in spring from overwintered plants. This ensures genetic consistency and allows for precise timing of blooms.

Phlox can be propagated from root cuttings taken in early spring or stem cuttings in early summer. Root cuttings are particularly effective for tall garden phlox.

Salvias vary in their propagation preferences by species, but many ornamental types root well from softwood cuttings taken in late spring or summer.

Woody Perennials

Roses are commonly propagated from hardwood cuttings taken in late fall or softwood cuttings in early summer. While roses can be grown from seed, cuttings preserve the exact characteristics of the parent plant.

Lavender propagates reliably from semi-hardwood cuttings taken in late summer. Remove lower leaves and plant in well-draining propagation mix with bottom heat for best results.

Advantages of Cutting Propagation

Cuttings produce genetically identical plants to the parent, ensuring consistent flower color, form, and growth habits. This method is faster than seed propagation for perennials and allows gardeners to preserve favorite cultivars that might not come true from seed.

Other Propagation Methods

Division

Division involves separating established clumps into smaller sections, each with its own root system and growing points.

Daylilies are easily divided in early spring or late summer by lifting the entire clump and separating it into sections with a sharp spade or knife. Each division should have both roots and foliage.

Hostas respond well to division every 3-5 years. The best time is early spring when new growth is just emerging, making it easy to see natural division points.

Iris should be divided every 3-4 years after blooming. Lift the rhizomes, cut them into sections with fans of leaves, and trim the foliage to reduce water loss.

Peonies can be divided, but they resent disturbance and may not bloom for several years after division. If division is necessary, do it in early fall, ensuring each section has 3-5 eyes.

Bulbs, Corms, and Tubers

These specialized storage organs naturally produce offsets that can be separated and grown into new plants.

Daffodils produce bulb offsets that can be separated when the foliage dies back. Smaller bulbs may take 2-3 years to reach blooming size.

Gladioli form new corms each year, with the old corm often producing several smaller cormels. These can be separated and grown on to flowering size.

Dahlias grow from tubers that can be divided in spring. Each division must include a portion of the stem with at least one growing eye, as eyes don't form on the tuber itself.

Begonia tubers can be cut into sections, with each piece containing at least one growing point. Allow cut surfaces to dry and callus before planting.

Specialized Techniques

Layering works well for plants that are difficult to root from cuttings. Bend a flexible stem to the ground, wound the underside slightly, cover with soil, and wait for roots to form before severing from the parent plant. This technique works well with climbers like clematis.

Grafting is primarily used for roses, where desired varieties are grafted onto hardy rootstock. This combines the desirable flowering characteristics of one plant with the vigor and hardiness of another.

Tissue Culture is a commercial technique used for mass propagation of plants like orchids and some specialty perennials. While not practical for home gardeners, it's how many of the plants we purchase are produced.

Choosing the Right Method

Consider these factors when selecting a propagation method:

Genetic consistency: If you want plants identical to the parent, choose vegetative methods like cuttings or division rather than seeds.

Speed to flowering: Seeds often take longer to produce flowering plants, especially for perennials. Cuttings and divisions typically bloom sooner.

Cost and quantity: Seeds are economical for producing many plants, while cuttings and division are better for smaller quantities of specific cultivars.

Success rates: Some plants simply propagate more reliably through one method than others due to their natural biology and evolution.

Timing and season: Different methods have optimal timing throughout the growing season, which may influence your choice based on when you want to propagate.

Understanding these propagation methods allows you to work with each plant's natural tendencies, leading to higher success rates and healthier flowers in your garden. The key is matching the method to both the plant's biology and your gardening goals.