GROWING SUMMER FLOWERING BULBS
Summer flowering bulbs, corms and tubers are many and varied. They fit in with most mixed planting schemes. There are tall varieties, which are useful for cutting and also to add height among summer bedding plants. Shorter types are ideal for rockeries and at the front of borders. The bulbs are best planted in late spring and will usually flower within a couple of months. There are also varieties that make excellent container plants.
On Arrival
Your bulbs should be planted straight away on arrival. For best results, we recommend growing Begonia corms on in containers indoors until risk of frost has passed (usually late May), after which, they can then be re-planted or positioned outside. Lilies, Dahlias and Gladioli should be planted straight outside unless the ground is waterlogged or frozen, however it’s best to protect the young growth with mulch or fleece until risk of frost has passed.
Bulbs, Tubers & Corms
Your plants are supplied as either bulbs, tubers or corms:
Bulbs (Lilies) Typical bulb shape, but with fleshy scales. The under-side of the bulb has long, visible roots.
Tubers (Dahlias) Tubers are a thick, fleshy underground stem/root. Sometimes they have fine roots attached and small visible buds.
Corms (Gladioli, Begonias) Usually round and quite flat in shape. The top side of Begonia Corms is concave and the bottom side is sometimes slightly convex.
Before Planting
Bulbs prefer free-draining soil. For best results, dig in some coarse sand or grit before planting to aid drainage if soil is heavy or compacted.
To give your plants an extra boost and to maximise flowering, rake some fish, blood and bone or Organic Extra dry Farmyard Manure into the surface of the soil before planting.
Planting Instructions
- Dig a hole with a trowel 2 – 3 times the depth of the bulb.
- Loosen the soil at the bottom of the hole. If your soil is very heavy or clay, mix in a good handful of grit or sand too.
- Position the bulb at the bottom of the hole in an upright position (with the pointed end facing upwards) and backfill the soil.
- Firm down the soil with your hands and water-in.
- Spacing: Allow about 8in/20cm between bulbs.
- Some Lilies require support to stop them falling over particularly Skyscraper types.
Planting Dahlia Tubers:
- The tuber should be planted horizontally with the old stem at the top, so dig a hole that’s wide enough to accommodate it and about 5in/12cm deep.
- Loosen the soil at the bottom of the hole. If your soil is very heavy or clay, mix in a good handful of grit or sand too.
- Position the tuber at the bottom of the hole. Position the bulb with any visible buds pointing upwards.
- Backfill the hole and firm down with your hands. Water thoroughly after planting.
- Spacing: Allow about 24in/60cm between tubers.
TOP TIP: Mark where you have planted bulbs with a cane. To avoid accidental disturbance before they start to grow.
Planting Begonia Corms:
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Begonias are best started in containers indoors as they are tender and need a longer growing period.
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Plant the corms close to the surface ensure the bulb is position the right way up. The concave side of the corm should be facing upwards.
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Cover the corm with a fine layer of soil – the edges of the corm should only just be visible.
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Spacing: Allow about 30cm/12in between corms.
Planting Bulbs or Corms in Containers
- Place broken crocks or polystyrene in the base of the pot.
- Half fill with compost and place bulbs on top.
- Cover bulbs, firm compost gently, and water well.
- If using Begonias plant the corms close to the surface with the concave side pointing upwards.
- Loosen the soil at the bottom of the hole. If your soil is very heavy or clay, mix in a good handful of grit or sand too.
- Position the bulb at the bottom of the hole in an upright position (with the pointed end facing upwards) and backfill the soil.
- Firm down the soil with your hands and water-in.
- Allow about 8in/20cm between bulbs.
After Flowering
Not all summer bulbs are fully hardy. After flowering, but before the weather turns really cold, those of a more tender nature will need to have their crowns covered with a thick mulch of peat, compost or leaf mould.
Alternatively, some plants (particularly Dahlias and Begonias) should be lifted and stored for the winter. The best time to do this is when the foliage has died down: cut the foliage back to 1” above the soil surface and dig up the tubers or corms with a garden fork. Shake off excess soil and store in a light, frost free place over winter, in a wooden crate or cardboard box, submerged in dry compost is ideal.
NB - There’s no need to water bulbs, tubers or corms when in storage as this may cause the bulbs to rot.
