Main methods of vegetative propagation of ornamental plants and flowers

Division of clumps, rhizomes, and propagation of bulbous plants

Vegetative propagation is the primary working tool in commercial floriculture. This method allows for a significant reduction in the time required to obtain ready-to-use planting material and fully preserves the valuable cultivar characteristics of the mother plant. Furthermore, it is the only way to reproduce ornamental species and forms that do not set seed in local climatic conditions.

• Height of shoot pruning during division — 5–15 cm
• Length of rhizome segments — 1–10 cm
• Growing-on period for bulbils — 2–3 years
• Drying time for corms before planting — 48 h
• Drying temperature for divided tubers — 21 °C

Division of the clump is one of the simplest, most accessible, and most common propagation methods. It guarantees rapid establishment and flowering, although it yields a relatively small volume of new planting material. The method is used when propagating the following plant groups:

• Herbaceous perennials of the open ground: bellflower, monarda, rudbeckia, phlox, echinacea, etc.
• Evergreen crops: asparagus, aspidistra, sansevieria, cyperus.
• Flowering shrubs: hydrangea, lilac.

For division, the clump is carefully dug up, the aerial part is pruned to a height of 5–15 cm, and it is cut using a sharp shovel or knife. Some plants can be pulled apart by hand. Each resulting division must have a developed root system and at least 2–3 viable buds.

Bulbous plants (hyacinth, narcissus, lily, fritillaria, tulip) are propagated by daughter bulbs (bulbils) that form underground. They are separated from the mother plant and sent for growing-on until they reach a marketable size.

To artificially stimulate the formation of bulbils, special technological techniques are applied:

• Damaging the basal plate of the bulb (carving, cross-cutting, or punching with a tube). This activates meristematic cells in hyacinths or awakens dormant buds in narcissi. When optimal temperature, humidity, and lighting are maintained, a mass of small bulbs is formed, which are grown on to flowering for 2–3 years. The method is also used for snowflakes, muscari, snowdrops, and squills.
• Scale propagation. Removing scales from the bulb causes micro-injuries that stimulate the division of meristem cells. In a moist and warm substrate, new bulbils are initiated at the base of the scales. Propagation is carried out using both individual scales (hyacinth, lily) and twin-scale segments with a piece of the basal plate (hyacinth, narcissus).

Some lily species (bulbiferous lily, tiger lily) are propagated by aerial bulbils. They are collected from the leaf axils and planted in protected or open ground. Marketable flowering bulbs are formed by the 2nd year with this method.

Propagation by corms and tubers

Cormous crops (acidanthera, gladiolus, crocus, crocosmia, freesia) replace the mother organ annually. During the growing season, a new corm forms at the base of the stem, and small bulbils form between it and the dying old one. Over two years of growing-on, they turn into adult corms capable of producing a flower stalk.

For cultivars that are reluctant to form bulbils, corm division is used to increase the propagation rate. The corm is cut into parts so that at least 1–2 buds remain on each.

Preparation of divided corms for planting includes the following technological stages:

1. Dust the cut surfaces with fungicide powder or crushed charcoal to protect against infection.
2. Lay the prepared parts out on mesh trays.
3. Dry for 48 hours in a warm and dry room.
4. After the protective cork layer has formed, plant the parts in pots or open ground.

Tuber propagation is used when growing anemone, tuberous begonia, gloxinia, caladium, and some buttercup species. Division is carried out in spring, before the active sprouting of buds. The tuber is cut with a sharp, clean knife into parts, each of which must have at least one bud. The cut surfaces are immediately treated with a fungicide or charcoal powder.

Before planting, tuber pieces must be dried for two days in a warm (21 °C), dry, and well-ventilated room, after which they are planted immediately. During the winter period, mother tubers are kept in dry and cool storage facilities.

Propagation by runners allows you to quickly obtain a dense carpet of ornamental plants without extra costs. The plants themselves form horizontal shoots, which easily root and produce daughter rosettes. The agronomist's task is to help them form a strong root system and transplant them to a new location in time.

1. Soil preparation. In autumn, apply compost around the mother plants to provide nutrients for future shoots.
2. Thinning. In early summer, remove the weakest runners. Evenly distribute the remaining ones and press them slightly into loose soil.
3. Fixation (alternative method). Bury pots filled with a nutrient mixture around the mother plant. Secure the runners in them using a wire staple.
4. Transplanting. After rooting, dig up the young plants and move them to their permanent location.

This method is optimal for the following crops:

• bugleweed (Ajuga reptans);
• creeping avens (Geum reptans);
• mock strawberry (Potentilla indica);
• sweet violet (Viola odorata);
• strawberry begonia (Saxifraga stolonifera).

Propagation by offsets

Offsets are formed from buds in the root collar zone and are lateral shoots — either aerial or subterranean. This method is widely used when growing succulents and certain tropical crops. The main task when working with them is to stimulate their formation and carry out proper rooting.

1. Separation. In spring, carefully separate the formed offsets from the mother plant.
2. Planting. Plant the obtained material for rooting in a loose nutrient substrate.

The method is effective for propagating such crops:

• agave;
• pineapple;
• houseleek (Sempervivum);
• jade plant (Crassula);
• echeveria.