Corms, rhizomes and tubers are generally classed as bulbous plants. Don’t worry about which is which: the differences between them are of interest mainly to botanists. All these plants work in much the same way, with the swollen parts storing food and water when resting.
Many house plants die back once they finish flowering. Some, such as, are best discarded, but others, such as Tuberous-rooted and , are long lived, and just need a rest. When stored in the right conditions, they will flower year after year.
Getting ready for storage
House plants of this type are in flower every month of the year, so you can’t go by the calendar alone. Once flowering is nearly over, stopand gradually reduce . Nip off faded , but allow the to wither naturally to send food supplies to the base for storage. You can move the plant to a less obvious spot, but don’t cut off the dying foliage, or you’ll shorten the plant’s life. When and dry off completely, cut them off at the base, being careful not to damage the rhizome, corm or tuber.
How and where to store
Store resting rhizomes, corms and tubers in their, just as they are, or dig them out, shake off the mixture, and store buried in a shallow box of dry peat or sand. This way, you can inspect them for any sign of rot. A small patch can be cut away with a sharp knife and dusted with fungicide; discard heavily infected ones, as they are likely to die, and may infect nearby plants in storage.
Temperatures vary according to plant. African Lily needs cool but frost-free conditions, while Tuberous-rooted Begonia needs a minimum of 7°C (45°F), and the tropical Angel’s Wings must have at least 15°C (60°F).
corms that have been correctly stored during the rest period can be planted out in the early autumn for a beautiful spring .
A totally dormant plant needs no light, so a dark cupboard,or garage is fine. Choose somewhere dry, ventilated and free of mice, and make a note of where you put the plants! Most dormant house plant corms, tubers and rhizomes should be kept dry, though African Lily and Tuberous-rooted Begonia like a touch of water from time to time.
Starting into growth
Beginlightly when growth starts again – often, but not always, in spring. house plants, for example, start into growth in July, while Arum Lilies grown as house plants start in autumn.
Repot the rhizomes, corms and tubers in fresh potting mixture then, too. Some may have tiny offsets round the base. Pot these up separately, but don’t expect flowers for at least a year. Gradually increase watering and move to a brighter, warmer spot to help the plant ‘wake up’. Once there are signs of growth – new leaves and shoots– you can start.
By correctly storing corms, rhizomes and tubers during their resting period, you can ensure they wake with renewed energy and grow more strongly.
Storing outdoor corms, tubers and rhizomes
Tender corms, rhizomes and tubers, such asand , need protection from hard frost while they rest. If you live in a mild, sheltered area, you may not have to lift them at all, and a thick mulch will do. In most places, though, it is safer to overwinter them inside.
When to lift and store
When their leaves and stems turn yellow in autumn, plants are starting to rest. Lift them before the first frost, using a trowel or hand fork. Try not to scrape or pierce the rhizomes, corms or tubers – pests and diseases enter through wounds. If frost threatens and the plants are still green, try to repot the plants in damp peat indoors to die down.
How to store
- Remove dead leaves, old , and as much soil or potting mixture as possible. Trim the stems back to 2.5cm (1 inches) from the base. Dry before storing. Place in a single layer on a garden sieve, paper-lined tray or wire mesh rack, in a dry, well-ventilated spot.
- When dry, inspect for pests and diseases, and shake off any remaining potting mixture. Place rhizomes, corms and tubers on a bed of dry peat in shallow boxes, then cover with more peat.
- When plants have started to rest, choose a dry day, before the first frost, to carefully lift them. Use a trowel or hand fork.
- When preparing for winter storage remove as many dead leaves, old and as much soil or potting mixture as possible.
Types of bulbous plants
- True bulbs, such as , have swollen bases. Tubers, such as and Begonia, have swollen stems or roots. Corms, such as Crocus, have flat, swollen bases.
- Rhizomes, such as Cupid’s Bower, can be identified by swollen horizontal stems.
- Thick-rooted plants, such as African Lily, are sometimes classed as bulbous, even though they aren’t, technically.
House-plants to store
- African Lily (Agapanthus)
- Arum Lily (Zantedeschia)
- Cupid’s Bower (Achimines)
- Tuberous-Rooted Begonia