Planting bulbs

Bulbs are ideal for anyone who rates themselves as 'keen-but-clueless' because they are one of the easiest plants to grow. Provided you plant them at the right time of year at more or less the right depth, they will reward you year after year with a reliable display of blooms.

When should I plant?

The planting time for bulbs varies broadly according to their flowering time. Spring-flowering bulbs should be planted from early autumn, so they have time to produce new roots before the onset of winter. Tulips are the main exception to this rule because they can be planted in late autumn or even early winter without adversely affecting the flowering for the following season. Summer-flowering bulbs, such as Tigridia and gladioli, and autumn-flowering bulbs, such as colchicums and nerines, are best planted from late spring onwards (see table, below).

Type of bulb	Planting time	Depth	Spacing
Allium	early autumn	5-7cm (2-3in)	15-30cm (6-12in)
Anemone	early autumn	5cm (2in)	10cm (4in)
Arum	mid-summer	15cm (6in)	10cm (4in)
Begonia	spring	2.5cm (1in)	22-30cm (9-12in)
Chionodoxa	early autumn	2.5-5cm (1-2in)	7cm (3in)
Colchicum	late spring	7cm (3in)	10-15cm (4-6in)
Crocus, spring	late summer	5-7cm (2-3in)	10cm (4in)
Crocus, autumn	mid-summer	5-7cm (2-3in)	10cm (4in)
Cyclamen	late summer	2.5cm (1in)	15cm (6in)
Eranthis	late summer	2.5-5cm (1-2in)	10cm (4in)
Erythronium	late summer	5-7cm (2-3in)	10cm (4in)
Fritillaria	early autumn	5-7cm (2-3in)	15-45cm (6-18in)
Galanthus	late summer	7-10cm (3-4in)	10cm (4in)
Gladiolus	mid-spring	7-10cm (3-4in)	10-15cm (4-6in)
Hyacinthus	early autumn	10cm (4in)	20cm (8in)
Iris reticulata	autumn	7-10cm (3-4in)	10cm (4in)
Leucojum	late summer	7-10cm (3-4in)	10-20cm (4-8in)
Lilium	mid-autumn	10-15cm (4-5in)	15-45cm (6-18in)
Muscari	late summer	5-7cm (2-3in)	10cm (4in)
Narcissus	late summer	5-12cm (2-5in)	10-20cm (4-8in)
Nerine	spring	2.5cm (1in)	15cm (6in)
Ornathogalum	mid-autumn	5-7cm (2-3in)	10-15cm (4-6in)
Puschkinia	early autumn	5-7cm (2-3in)	7cm (3in)
Scilla	late summer	5-7cm (2-3in)	5-10cm (2-4in)
Sternbergia	mid-summer	7cm (3in)	12cm (5in)
Tigridia	late spring	5-7cm (2-3in)	15cm (6in)
Tulipa	late autumn	7-15cm (3-6in)	10-20cm (4-8in)

Planting tips

All bulbs should be planted with the 'nose' (pointed bit where the shoot comes out) at the top and the 'basal plate' (flat bit where the roots are produced) at the bottom. The only exception to this rule is with crown imperials (Fritillaria imperialis)which are hollow and should be planted on their sides to prevent rotting. To achieve a natural-looking swathe of bulbs you will need to plant them in irregular blocks at variable planting distances. If you find this difficult, try scattering the bulbs and planting them exactly where they land. Where only a few bulbs are being planted, use a strong trowel or one of the special cylindrical bulb planters to make the hole. For larger swathes of bulbs use a spade to dig out a planting block to the correct depth, position the bulbs and then replace the excavated soil. On heavy soils, like mine I would recommended sitting the bulbs on a layer of sharp grit to aid drainage and help prevent rotting.

Planting in lawns or under trees is very similar. When planting in lawns, carefully peel back the turf, then dig out the soil and plant the bulbs. Once the soil has been replaced and consolidated by treading lightly, you can replace the turf and fill any gaps with sieved garden soil. Under trees, planting bulbs singly is the best option because large excavations will cause more damage to tree roots and may encourage suckering. If you have had problems with rodents such as mice and squirrels digging up and eating your bulbs in the past, try covering the planting area with a layer of chicken wire buried just below the surface.

Planting in cages

Cut back after planting It is well worth cutting back newly planted climbers by two thirds. This will encourage lots more side shoots to tie in. The growth hormones in climbers make them shoot straight upwards, creating a tall leggy specimen that's bare at the base. By cutting back that top growth you encourage buds lower down to shoot and grow out sideways, producing a bushier plant. It might seem brutal to cut back something newly planted, but the end result will be a much healthier, fuller plant.