Lipstick plant

Identification and origin

Aeschynanthus radicans belongs to the family Gesneriaceae, the same family as the African violet and the gloxinia. It is native to Southeast Asia: from Myanmar and Thailand through the Malay Peninsula to Sumatra, Borneo, and Sulawesi. In the wild it is an epiphyte of humid forests, growing anchored on tree branches, from which its slender stems arch and then trail.

It is an evergreen perennial with a vining habit. Its opposite, elliptic to oval leaves are 3–6 in long. Thick, smooth, and leathery, they store water that helps the plant through dry spells; they are dark green and often edged in red. In cultivation the plant fills a space of 12 in – 3 ft, and its maximum height is between 20 in and 3.5 ft.

The flowers appear in dense clusters at the stem tips. Each bud first emerges from a dark purple, tube-shaped calyx, exactly like lipstick rising from its case. It then opens into a scarlet tubular flower with a yellow throat, 1–3 in long, with five lobes, the upper ones shorter than the lower ones. Flowering is generous and runs from spring to fall; up close, the flowers have a rather unpleasant smell. The fruit is an elongated capsule about 2 in long.

The genus name comes from the Greek aischyne, “shame,” and anthos, “flower,” probably referring to the red blooms; the epithet radicans means “rooting,” because the stems produce roots. Several cultivars are common: ‘Mona Lisa’, with orange-red flowers; ‘Tangerine’, with yellow-orange flowers; ‘Curly’ and ‘Rasta’, with twisted leaves; ‘Twister’; and ‘Variegata’, marked with white, cream, and yellow.

Light

Give it bright but filtered light: that is what lets it grow well and bloom. Avoid full sun, though. Near a bright window screened by a sheer curtain, the plant is right at home. It also adapts to artificial grow lights, which are handy in a dark room.

If it spends the summer outdoors, put it in part shade, never in full sun.

Watering

This is a thirsty plant: never let it suffer from drought, especially in a hanging basket, where the mix dries out quickly. Water as soon as the surface of the mix starts to dry, using tepid water, to keep the mix moist but never soggy. Water should drain freely from the bottom of the pot. Avoid wetting the foliage with cold water, which can discolor it.

In winter the plant grows less: water sparingly and let the mix dry a little more between waterings. This cooler, drier rest encourages bud formation for the next round of flowers.

It likes high humidity, but with moving air: humid, stagnant air encourages fungal diseases. Group plants together or keep it in a bright bathroom, and keep the leaves dry and out of contact with the potting mix.

Potting mix

Its epiphytic roots need a light mix that is rich in organic matter and drains very well. An African violet mix with added sphagnum moss and a little crushed charcoal suits it; a peat-free houseplant mix is another option. The ideal pH is close to neutral.

During the growing season, from mid-spring to late summer, apply a half-strength liquid fertilizer once a month, for example an orchid fertilizer, which supports both leaf growth and flowering. Stop feeding in winter.

Temperature

During active growth it does well when its potting mix stays between 64 °F and 70 °F. At night, 61–70 °F suits it. In winter it accepts slightly cooler conditions, which help it set flowers, but it remains a warm-greenhouse plant that prefers not to drop below 59 °F. Below 50 °F, it sheds its leaves.

Keep it away from cold air currents, doors, and heating vents. In the ground it can only be grown in USDA zones 10a to 11b.

Repotting

Grow it in a pot or hanging basket that always has drainage holes. Repot when it dries out very quickly after each watering and makes little growth, a sign that the roots fill the whole pot: move it to a container only slightly larger. Algae on the surface also indicate a sour mix that needs replacing.

Use the same light, free-draining mix, enriched with sphagnum moss.

Pruning

After flowering, cut the stems back to about 6 in long to encourage new shoots, which will carry the next flowers. Throughout the year, remove weak or overly long shoots.

If the plant looks straggly, cut the longest stems back as far as 2 in. If no new growth follows, reduce watering and hold off on fertilizer until it recovers.

Propagation

Stem cuttings are easy and reliable. In spring, take a soft stem with three nodes, or a semi-ripe stem in summer. Keep only the top two to four leaves, dip the base in rooting hormone, and insert it in a mix of equal parts vermiculite and perlite. Keep the mix moist: roots appear in about two weeks.

Stems removed when you prune after flowering make good starting material. Once the roots are well formed, move the young plants into the light mix described above.

Common problems

• Lower leaves dropping: cold air currents, irregular watering (too much or too little), or temperatures below 50 °F.
• Pale or brown spots on the leaves: cold water on the foliage, or leaf spot disease.
• Gray mold (botrytis): stagnant, humid air, wet leaves, or leaves touching the potting mix.
• Few or no flowers: too little light, no cooler, drier winter rest, or too little fertilizer during the growing season.
• Long, bare stems: a plant that was not cut back after flowering.
• Pests: aphids, mealybugs, scale insects, and mites. Check leaf undersides and stem joints; fine webbing and stippled foliage point to mites.

The same symptom can have several causes: before acting, check light, moisture in the mix, temperature, and the condition of the roots.

Toxicity

No toxicity has been reported: lipstick plants in the genus Aeschynanthus are classed as non-toxic to dogs, cats, and horses, and no toxicity to people has been reported. As with any houseplant, it is still best to keep pets and young children from chewing the leaves.