Bulbs are one of the easiest and most versatile plants we can grow, and there is a flowering bulb for every time of the year.
In autumn, displays of colourful pictures above trays or packets, of various shaped and coloured bulbs appear in garden centres, nurseries and stores tempting us with the promise of spring displays. Before you rush over to the marketplace to fill your basket with these self-contained packets of life, I am hoping I can give you a few tips on how to get the best from these beautiful performers.
What Are Bulbs?
The word 'bulbs' is a label used to talk about a range of plants that all form an underground storage organ for the energy they need to grow the following year.
Everyone will have a thin, flat plate at the bottom which the roots will grow down and the stem will grow up from. The bulk of a bulb is referred to as 'scales', which are modified leaves. These contain the stored energy (sugar), which makes an onion taste so good. If you would like to know more about the different types. Pimlico Dan wrote an article to explain the differences.
As a general guide, bulbs are best planted three times their own height in-depth, so a 5 cm long tulip bulb needs a hole dug 15 cm deep. And always remember to place the bulb point end up, so the plant doesn't use up energy turning itself right way up.
With some (Garden Anemone) this is harder then it looks, if you're not sure, you can plant them on their sides, the growing stem will then only have to bend around a little.
Bulbs perform best if they are planted as soon as possible after purchase, but if you're not ready and need to store them for a while place them in a cool, dark and dry place. And to quote Jonathan Moseley "Put a post-it note on your fridge reminding you where you've put them" ... I know I'm not the only one to have discovered bulbs two months down the line.
Growing Bulbs Outdoors
Whether you want to grow your bulbs in the lawn, or amongst your plants, you will need to consider the following.
- Improving the soil. Most bulbs do not like sitting in wet conditions which causes them to rot. If you know your soil is heavy, you may need to dig well-rotted garden compost or animal manure and horticultural grit into the area before you plant. This will help an excess water drain away.
- Spacing out To me bulbs planted en-mass, always look more attractive and natural. One tip to avoid straight lines is to gently throw your bulbs over the area you want them to grow and dig them in where they fall. Ideally, they need to be twice the bulbs width apart to give them space to grow, but you don't need to be too strict on this.
- Digging the hole: You can either use a bulb planter to take out a plug of soil to the right depth, or a bulb trowel which is usefully marked with cm and inches on the blade to help you gauge the depth. In compacted areas, under larger shrubs or spaces filled with tree roots, you could also use an auger attached to a hand-held drill (also useful for drilling plant stake holes!)
- Feeding: Although the bulb will contain all the energy it needs to grow large enough to start producing more energy, we can give it a helping hand by providing additional feed that will help to improve the flower. This will need to be applied in the spring once the leaves have appeared.
Growing Bulbs in Containers
If you want to grow bulbs in outdoor containers you follow the same rules as if you were planting in the ground; however, if you would like to create a prolonged display, the bulbs can be planted closer together and in layers. They will require more care in regards to regular watering and feed, but the effect is stunning.
I gave some additional tips and advice on growing in containers, in the article Spring bulbs, it's not too late!.
Always buy the biggest bulbs you can afford as they will produce bigger and better displays. This Amaryllis bulb was almost as big as my hand.
Growing Bulbs Indoors
Many people like to grow bulbs indoors over the winter months for colour and decoration, and Candide has published several how-to articles to inspire and help you plan, grow and enjoy.
What to do in the Autumn season
Alan has written a useful guide on what autumn flowering bulbs need to be planted now, and Pimlico Dan has written about which flowering bulbs can give us autumn and spring flowers.
We have also put together a collection of the different spring flowering bulb families that need to be planted in autumn. Hopefully, they will give you some inspiration.
Although not grown for their flowers, now is also the time to plant some vegetable bulbs.
and Shallots such as S. 'Hâtive de Niort', S. 'Longor' and S. 'Griselle'
TIP, Always label your pots: Candide user Spekboompie asked the community if anyone knew what these inherited bulbs were.
Bulbs planted in the ground can benefit from an 8 cm (3") mulch layer of well-rotted garden compost or animal manure being spread over them just before the first frosts.
Many bulbs need a dormant cold spell to prompt them into spring growth, but a mulch layer (once pulled down by the worms) will help to feed the soil and keep the structure of the ground open. This will enable roots, water and air to pass through.
It also helps to maintain the soils moisture and temperature levels by slowing the passage of any winter rains and reducing the effects of any heavy frosts.
You shouldn't need to move the mulch away in spring as the leaves will push up through.
Once your bulbs have started to emerge, we can improve their display by giving them a helping hand.
- Feed: Scatter a slow-release granular feed around the base of the plants as soon as the leaves appear and then every two weeks water on a liquid feed until the leaves begin to fade.
- Water: If we get a repeat spring heatwave, our bulbs will need watering every seven to ten days. We will also need to carry on after the flowers have finished helping the bulbs "fatten-up" for next year.
- Deadhead; by snipping off the flowers when they begin to fade, not only do we keep the plants looking a little tidier, but we also prevent the plant from spending precious energy on producing seeds. Instead, it will concentrate on replenishing its bulb for next year. Commercial bulb growers call this 'Topping'.
- Leave the foliage; for as long as possible, before pulling it up. Ideally, until the leaves have started to go yellow. At this point, the plant has stopped photosynthesising and is drawing back nutrients from the leaves into the bulb. The foliage can look very untidy and last for what seems like ages, but the longer you can leave it, the better your display will be next year.
- Marking clumps to move or divide: After a few years bulbs can develop into thick clumps all competing for the same food and not getting enough space to produce flowers. These will need digging up in the summer and dividing (to be replanted elsewhere, given away or sold on online marketplaces. To help you find the right spot once the bulbs are dormant, now is the time to stick a cane in the ground.
Some bulbs such as Snowdrops are best moved when they are "In the green" Nic Wilson wrote this guide.
And if you wanted to find out more about this late winter wonder, Helen gave us an introduction to the Chelsea Physic Gardens collection, and you can read about how to become a Galanthophile.
- Clear away: finishing tidying up the dead leaves to help control and pest or disease from building up.
- Lifting: Now the bulbs are dormant it is the time to lift clumps you marked in spring. You can either replant straight away or store them for autumn planting in a cool, dry and dark place. This could be the crisper drawer in the fridge, provided you do not use it for ripening fruit at the same time, Ethylene emitted by the fruit will prevent the flower bud from developing.
Visit gardens and shows for inspiration throughout the spring and summer. Image by JoanneMartha
- Plan, next years bulbs: The bulbs we buy have been grown to provide a stunning display in the first year. They will flower again in following years, but their performance will decrease as they concentrate their energy on the production of offsets. The parent bulb is feeding these baby bulbs at the cost of flower production. They can be dug up, separated and grown on, producing their own flowers in a few years time. However, for container-grown bulbs which have had to work a lot harder, it is sometimes worth considering them to be a one-year investment and treat yourself to new colours and varieties every year.
If you wanted to find out more about how the tulip bulbs we see on our shelves are farmed, I recommend this video. Oh to have their sandy soil!