Successfully Propagating Hibiscus

Large blossoms and vibrant colors – it’s no surprise that hibiscus is a favorite among hobby gardeners. Here’s how you can successfully propagate your hibiscus plants.

Propagation Methods

There are several ways to propagate hibiscus. The hardy garden or shrub hibiscus (Hibiscus syriacus), commonly grown in outdoor gardens, are cultivated varieties. These need to be vegetatively propagated to maintain specific characteristics like flower color. The most reliable method is grafting, as cuttings tend to root poorly under amateur conditions. Seed propagation is mainly used in breeding to create new varieties and to raise seedling rootstocks for grafting.

The Chinese hibiscus (Hibiscus rosa-sinensis), also known as tropical or rose hibiscus, is typically grown as a houseplant, though it can also spend summers on balconies or terraces. It is best propagated via tip or section cuttings.

The hardy perennial or swamp hibiscus (Hibiscus x moscheutos), which also thrives in gardens and is relatively winter-hardy, can be propagated by seed or true-to-type by cuttings.

The flowers of Hibiscus rosa-sinensis (above) and Hibiscus x moscheutos (below)

Propagating Hibiscus by Seed

To grow garden hibiscus from seed:

• Harvest the dried seed pods in autumn.
• Note: Hibiscus doesn’t reliably produce seeds every year—only after long, warm summers.
• Seeds can also be purchased from garden centers.
• Store seeds cool and dry through winter.

Sowing:

• Sow seeds under glass in March.
• Alternatively, sow directly into the garden after the last frost.
• It takes at least 4–5 years for seed-grown plants to flower.
• Swamp hibiscus flowers earlier, despite being grown from seed in the same way.

Garden hibiscus often self-seeds, but offspring may differ in flower form and color. These wild seedlings make good rootstocks for grafting or can be carefully dug up in early spring and transplanted to a new spot.

Tip: If you plan to use the seedling for grafting, grow it in a pot for one year before grafting the following spring.

Grafting Hibiscus

Grafting is especially effective for vigorous garden hibiscus.

• Use potted seedlings (min. 7 mm thick) of Hibiscus syriacus as rootstock.
• Grafting period: Early January to mid-February.
• Methods: Cleft grafting, whip and tongue, or side grafting.
• Graft close to the root collar to avoid excessive wild shoot growth.
• Secure with raffia and seal with grafting wax.
• Keep grafted plants frost-free in a greenhouse or plastic tunnel.
• After rooting, transfer to larger pots, and grow them in a cold house/tunnel the first year.
• Transplant to the garden the following spring.

Important: Young plants are sensitive to frost, especially in exposed areas. Mulch the base in autumn with leaves or spruce branches.

Propagating by Root Cuttings

Certain varieties of Hibiscus syriacus (e.g., the dark red-flowering ‘Rubi’) can also be propagated using root cuttings, though these plants tend to grow less vigorously than grafted ones.

Instructions:

1. In autumn, cut finger-thick sections of fleshy roots.
2. Store in moist peat in a frost-free place until December/January.
3. Cut into 10 cm (4 inch) pieces.
4. Lay horizontally in seed-starting soil, 1–2 cm deep.
5. No watering needed initially, but keep soil moderately moist.
6. Place in a cool, dark location.

Once shoots emerge, move the young plants to a bright spot. Vigorous types can be planted outdoors in late spring; others should be kept in pots for one year.

Propagating by Hardwood Cuttings

Garden hibiscus can be propagated in winter using hardwood cuttings from the previous year’s growth.

• Cuttings should be taken in autumn, right after leaf fall.
• Cut into pencil-length sections and place in shaded, unheated greenhouses in moist, slightly clayey humus soil.

Success rate is low (approx. 5–10% root successfully), but rooted cuttings can be transplanted into the garden after frost danger has passed.

Propagating by Softwood Cuttings

All hibiscus species can be propagated by cuttings, but this method is most effective for:

• Chinese hibiscus (Hibiscus rosa-sinensis)
• Swamp hibiscus (Hibiscus moscheutos)

For Chinese Hibiscus:

• Take cuttings in spring, right after new growth.
• Remove flower buds, if present.

For Swamp Hibiscus:

• Best time: June

Use non-woody tip or section cuttings about 10 cm (4 inches) long.

• Slightly nick the base with a sharp knife.
• Apply rooting hormone powder (e.g., “Neudofix”).
• Plant 3 cuttings together in small seed trays or pots.
• Maintain a soil temperature of at least 22°C (72°F).
• Roots typically form within 3 weeks (even faster for swamp hibiscus).

Note: Chinese hibiscus is not winter-hardy. Young plants must be kept indoors or in a heated greenhouse. Swamp hibiscus can be planted outdoors after wintering indoors, but needs good winter protection.