Houseplants

Houseplants come in all shapes and sizes, many with architecturally stunning foliage, and others with beautiful blooms in every colour. Apart from regular watering and feeding, most require little attention. This short guide deals with houseplants which need to be indoors all year.

Anthurium makes an attractive houseplant. Image: RHS/John Trenholm

Quick facts

Group Mainly evergreen tender perennials, shrubs, climbers, palms, orchids, succulents and bulbs
Flowering time Variable
Planting time If needed, repotting is generally best carried out in spring
Height and spread Variable
Aspect Most prefer a warm place with even temperatures in bright filtered light
Difficulty Easy to difficult

Cultivation notes

Most houseplants require bright filtered light. Light levels decrease rapidly as plants are placed further back from the window. It is important to avoid sun through glass as this can scorch the leaves of tropical plants.

As light levels fall in the winter some plants may benefit from being moved to a lighter position such as nearer a window as long as the minimum required temperatures can be maintained.

Most houseplants thrive in warm rooms and even temperatures all year round.

During winter, move plants to rooms which are not overheated during the day, but maintain the required minimum temperatures. Avoid placing plants near open fires, radiators, in draughts, or on windowsills on frosty nights.

Tropical plants require a humid atmosphere. Mist plants daily, or, better, place on a tray of damp gravel, expanded clay granules (Hydroleca) or recycled lightweight aggregate (Hortag). Plants grouped together will create a humid micro-climate around their leaves.

Watering

  • Avoid overwatering as this can lead to root death and collapse of the plant
  • Let the surface of the compost dry a little before applying more water at room temperature. Allow the plant to take up water as it is needed or allow excess to drain away. Do not let the plant sit in water
  • Use rain water for acid lowing plants such as gardenia
  • In winter, gradually reduce watering until the compost is almost dry between watering and stop feeding, except where plants are growing vigorously or flowering

Feeding

  • Liquid feeds are generally the best. Choose one high in potassium for flowering plants
  • For foliage plants a more balanced feed is suitable. Controlled release fertilisers will last the growing season
  • Specialist feeds are available for certain groups of plants such as orchids
  • Most plants should only be fed when actively growing in March to September
  • Reduce feeding in winter and do not feed plants that are resting

Repotting

After a year or two plants may need repotting to maintain healthy growth. Choose a clean pot, one or two sizes larger than the original pot. Make sure that existing compost is moist before repotting into a similar medium. Never repot unless the plant actually needs it. The best time is spring.

A multipurpose compost, houseplant compost or loam-based compost will be suitable for most indoor plants.

Pruning and training

Pinch back shoots of young plants when in active growth to encourage branching. Trailing plants usually benefit from this treatment.

Most leafy, mature foliage plants need no pruning.

Many houseplants, with the exception of orchids and palms, can be renovated by cutting the old or damaged foliage back to base or by pruning to a healthy bud in spring. Water and feed well to aid recovery.

Propagation

Depending on the plant, houseplants can be propagated by division in spring (after flowering), softwoodsemi-ripe cutting or leaf cutting during the growing season or by seed.

Cultivar Selection

Top houseplants for different conditions;

Sunny windowsill: Hibiscus rosa-sinensis
Full filtered light: Justicia brandegeeana, Streptocarpus, Hoya carnosa
Medium light: Dracaena, Ficus, Philodendron erubescens, Mostera deliciosa
Low light: Aspidistra elatior, Philodendron scandens, Schefflera, Adiantum raddianum

For a fuller list see our page on choosing the best houseplants.

Problems

Houseplants can suffer from a few pest and diseases such as aphids, red spider mite, mealy bug and scale insect.

Overwatering, fluctuating temperatures and draughty positions are the main causes of leaf browning and drop. If your plant starts to brown, or leaves start to drop, look at your watering regime, and check room temperatures and draughts. This is a common problem in winter in centrally heated homes.

See our page on leaf damage on houseplants for more causes and remedies.

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