Start summer bulbs into growth
Whatever the weather, summer begins to feel like a possibility this month. Planting and planning for summer starts NOW!
Dahlias and summer bulbs such as lilies and gladioli can all be started into growth this month, extra spring warmth and increased moisture will encourage shoots to emerge from bulbs and tubers and coax these summer flowering plants back to life.
Unpack bulbs as soon as possible after delivery and plant them as soon as weather allows while they are fresh and in good condition. If it’s frosty or you have to store bulbs until you can plant them, keep the bulbs somewhere dry and frost free; cover them with fleece or paper, not plastic, and store them in something breathable, a cardboard or wooden pest-proof box is ideal.
To start summer bulbs and tubers into early growth, including dahlias, cannas, tuberous begonias and gladioli ,cover the bulbs and corms with a shallow covering of compost and keep in trays or pots of compost in cool frost free conditions. When green leafy growth appears they will be ready to pot up; grow them on in warmth and plant out into their permanent positions when the risk of frost has passed. We also sell many of our dahlias as young plants and they make superb summer bedding plants.
If you are planting summer bulbs, rhizomes, corms and tubers in beds and borders outside do it when the soil warms up. Stagger the planting over several weeks if possible, as the plants mature and flower in succession they’ll give a longer lasting display.
If you are planting summer bulbs into containers follow the method in our step by step guide but adjust the planting depths.We’ll send you a comprehensive bulb growing guide with every order but as a rough guide most corms, bulbs and tubers should be planted at least twice their depth in containers. Rhizomes are usually planted horizontally and more shallowly.
Plant Gladioli corms deeply-at least 15cm (6in) deep.
Plant Dahlia tubers horizontally with the old stem at the top and any visible buds pointing upward; plant tubers about 12cm (5in) deep.
Plant rhizomes horizontally, and very shallowly. Iris rhizomes should be planted with only half the rhizome submerged so the other half is exposed to the sun. When you plant irises ensure the rhizome is exposed but any fine roots are buried.
For best results, we recommend growing on Begonia tubers in containers indoors until risk of frost has passed (usually late May), they can then be re-planted into baskets and containers or positioned outside. Plant the tubers close to the surface with the concave side facing upwards. Cover with a fine layer of soil so the tuber is only just visible.