As nights draw in, keep your spirits up by looking ahead to Spring-flowering bulbs…
Broadly speaking there are two main types of bulbs: Spring- and Summer-flowering. (Incidentally, the term ‘bulb’ often refers not only to true bulbs, but also tubers, corms, and rhizomes.)
Spring bulbs: Also called ‘hardy bulbs’, these bulbs are planted in Autumn, spend Winter under ground, and break through to flower in Spring. Some of the more common Spring bulbs are Daffodils, Tulips, Hyacinths, Crocuses, Allium, Irises… These bulbs need several weeks of cold – even freezing – temperatures to break their dormancy and flower to full potential. Snowdrops (Galanthus) can be planted as bulbs in Autumn or ‘in the green’ (in leaf) in Spring.
Summer bulbs: Also called ‘tender bulbs’, these bulbs are planted in Spring and flower in Summer - Gladioli, Lilies, Colocasia, Dahlias… Some will bloom later in Summer or for a longer time, like Dahlias that bloom into Autumn. Summer bulbs aren't tolerant of cold temperatures and are planted only after the ground warms up and there's no longer a threat of frost. If purchased before planting time, store them in a cool, dry spot until planting.
How best to use bulbs in your garden
Bulbs can be naturalistically scattered into lawns, under trees, or planted through planting borders. Many bulbs will naturalise and multiply, coming back year after year.
Plant them in big drifts for greatest impact. (At a minimum, they should be clustered together for worthwhile impact.)
To make the effect natural, cast them by hand onto the ground and plant them where they land.
Take account of their expected flowering time (marked on the packet). You can plant a combination of early, mid- and late-season flowers to extend the season.
Hide dying foliage of low-growing bulbs that are past their prime with taller bulbs planted in front or with companion plants.
Many bulbs are perfect for container planting — bring them into view when in flower and move out of the way when foliage is wilting / when dormant. It’s OK to plant them much closer together in containers than specified for in-ground planting.
How to plant bulbs
Bulbs can be planted in layers by digging up an entire area down to the proper depth, placing the bulbs and covering; or in individual holes dug for each bulb. Individual planting is best done with a special bulb-planting spade or even a mini-augur.
Take note of the recommended depth for the type of bulb you’re planting – should be marked on the packet. Depth is important for bulbs. If planted too deep, they will bloom late or not at all. If planted too shallow, new growth may become exposed too soon and risk damage by cold temperatures. If you are unsure of the exact planting depth, a good general rule of thumb is to plant the bulb 2 to 3 times as deep as the bulb is tall.
Place the bulbs with the pointy-end up and with the roots down. If you’re not sure of the top or bottom of the bulb, plant it on its side and it will find its way to the surface.
Cover with soil and a light layer of mulch.
Layering bulbs in a pot for ‘non-stop’ flowering
You can plant bulbs with different sizes and staggered bloom times in layers for a continual flow of blooms. You’ll need quite a large container that is deep and wide enough. Along these sorts of lines:
A good layer of potting soil for a planting depth of about 20cm: place a few late-spring-blooming bulbs such as Daffodils or Tulips
Another layer of potting soil for a planting depth of about 15cm: place mid-spring-blooming bulbs such as more Tulips or Hyacinth or Daffodils.
Another layer of potting soil for a planting depth of about 10cm: add early-blooming bulbs such as Galanthus, Muscari or Crocus.
After-care for bulbs
After flowering, you should only cut the flower stem back. Leave the foliage intact, or at least until it turns yellow and wilts to the ground. This is because the leaves are gathering and storing energy for next year. If the foliage is cut back too soon, bulbs may not perform well—or at all—the following year. The old-fashioned habit of tying daffodil leaves into knots is definitely not recommended, however tidy it might appear.
Learn more about Robert Wadman, author of this post, here