Are you thinking of adding some bulbs to your garden? Whether you want to plant bulbs in containers or straight into the ground, this article will tell you all you need to know about caring for these magnificent plants.
From the diminutive spring snowdrop to the mid-summer glory of gladioli and the fiery autumn crocosmia, discover how to plant and care for our best-known flowering bulbs.
Bulbs are very easy to care for. They don’t need perfect conditions to grow and flower as they store everything they need, giving them an advantage over other plants.
Bulbs are also very easy to plant and most aren’t fussy about their location or soil, growing just about anywhere. Bulbs also don’t require you to have any special knowledge. As long as you plant them the right way up, they’ll reward you with stunning flowers each year.
Types of bulbs
There are many types of bulbs that are more accurately referred to as geophytes, but there is only one group of true bulbs.
True bulbs are layered structures with plant carbohydrates stored inside. In the middle of this structure is a plant shoot. The roots grow from the basal plate. The outer skin of this structure flakes away in layers and is flanked by developing bulbs.
True bulbs are usually spring bulbs like daffodils and tulips. True bulbs can be further divided into two categories: tunicate bulbs and imbricate bulbs.
Tunicate bulbs have flaky, paper-like outer skin referred to as a tunic. This layer of skin protects the interior scales from damage while carbohydrates are being stored. Tulips are tunicate bulbs.
Imbricate bulbs, unlike tunicate bulbs, need to stay moist prior to planting. They also lack the flaky, paper-like outer layer. Lilies are imbricate bulbs.
Rhizomes are underground stems that store carbohydrates and spread new growth. These stems usually grow horizontally under the ground. It will create new shoots and roots at intervals as it spreads under the soil.
An example of a plant with rhizomes is the irises. These rhizomes often become visible above ground as they spread. They are easy to pull apart to start new plants.
Corms are fleshy underground stems that grow vertically and store food for some plants. Corms also have a tunic, but when cut in half it doesn’t have rings as a bulb does. Corms spread readily and are very easy to care for. Plants such as gladioli, freesias and crocuses grow from corms.
Tubers are short, thick root-like organs that grow below the soil. They are used to store food for some seed plants. Each tuber has several nodes and can be used to propagate new plants. Daylilies, dahlias and cyclamen grow from tubers.
These are thickened roots that are designed to store carbohydrates for the plant to use. An example of a plant with tuberous roots is the begonia.
Bulbets, also called bulbits, are bulb-like structures that grow on top of plants. They are tiny round organs that appear after a plant such as an allium has flowered.
What to look for when buying bulbs
If you want your bulbs to look spectacular once they flower, it’s important to buy the best ones. Any sickly bulbs may not sprout or only create one or two blooms when flowering. Healthy bulbs are almost always guaranteed to sprout and create stunning blooms.
- Avoid buying bulbs that are obviously mouldy. If they only have a few blemishes or the mould rubs off, it should be ok as long as the bulb isn’t squishy, in which case, choose another.
- Check that the bulb’s tunic is in place as it helps to prevent the bulb from drying out.
- Avoid picking any bulbs with soft spots as these are the first signs of rot.
- Choose the bulbs that feel the heaviest. Very light bulbs may have dried out and died.
- When it comes to bulbs, size matters. Choose the biggest bulb of its kind for the best flowers. Look for the words ‘top size’ on the description if you’re unsure about what to look for.
When to plant bulbs
Here’s a guide to the planting time of different bulbs:
Bulbs to plant in spring (for summer/autumn flowering)
- Papaver (Oriental poppy)
Bulbs to plant in summer (for autumn flowering)
- Autumn crocus
- Autumn snowflake
- Adaptable cyclamen
Bulbs to plant in late summer/autumn (for winter/spring flowering)
- Grape hyacinths
- Winter aconites
- Dutch irises
Bulbs to plant in winter (for spring flowering)
How to plant bulbs
Step 1: Prepare the soil
Almost all bulbs like well-drained soil. If you have clay soil that doesn’t drain, you need to mix in a lot of grit to help it drain. Standing water will cause your bulbs to rot.
Step 2: Make the holes
Once you’ve read up on how close the bulbs can be placed to each other, you can start to dig a hole for them. A general rule for this is to plant the bulbs three times as deep as the height of the bulb. This isn’t true for all bulbs so make sure to check.
Step 3: Plant the bulbs
Once the holes are ready, place the bulb with the pointy end up. If you’re unsure of which end needs to go up, place the bulb on its side and it will correct itself. Cover with loose soil.
Step 4: Water your bulbs after planting
Newly planted bulbs need to be watered to settle in and start growing. Make sure the soil drains well. Keep the bulbs slightly moist by allowing the top 2.5 cm of soil to dry out before watering again.
Step 5: Protect the bulbs
If there are a lot of bulb eating critters in your area, you can protect the bulbs by placing chicken wire or something similar over the area to prevent them from being dug up.
Planting density for bulbs
Different bulbs have different planting densities. Here are two websites you can consult for different bulb planting densities:
Winter flowering bulbs (to plant in late summer or autumn)
Winter-blooming bulbs are among the hardiest plants and will flower through frost and snow. Whether you want to brighten a shady spot or plant up a selection of pots for a sunny patio, find details for our best-loved bulbs below:
Snowdrops offer their diminutive, bell-shaped flowers right in the depths of winter, delighting us at a time when there is little life in the garden.
Snowdrops are best planted in an area with partial shade. These bulbs will start to flower in late winter, brightening up your winter garden while all other plants are still dormant.
Snowflakes flower at almost the same time as snowdrops so planting these two sets of bulbs closely together will provide a splash of white flowers in any container or flower bed.
Crocuses usually brighten up your garden in early spring. It’s best to plant them in an area with full sun for the best flower display. The soil should be moist but drain well. There are different crocus species so make sure to read up on the specific one. Some crocus species bloom from autumn into winter instead of in spring.
Crocuses can be planted in large groups, creating a carpet of lilac, purple and yellow blooms.
Hyacinths are famous for growing in darkness in understairs cupboards, their blooms appearing just in time for Christmas. For festive flowering, plant them at the end of September and as soon as the flower bud shows, they can come out of the darkness into the light. Their scent is heavenly indoors and they can be moved out to the garden after they finish blooming, ready to bloom again next spring.
Winter aconites can be grown in shady corners of the garden in well-draining soil. They need to be planted about 5 inches deep in the autumn to allow them time to develop their bright yellow flower heads. Like most bulbs, they like to spread so if you want to avoid this, grow them in a container.
Anemones will flower at the end of the winter into the beginning of spring so plant them in June and July for flowers the following year. They are very easy to care for just plant them in any area with well-drained soil and either full sun or partial shade.
They can also flower at different times of the year depending on when you plant them. If you planted in spring, you can expect flowers in summer. Those planted in summer will flower in autumn while the ones planted in autumn will bless you with flowers later in winter or early spring.
Spring flowering bulbs (to plant in autumn)
The following bulbs are all perennials, meaning they will flower every spring. Many of them will spread naturally so they are great value for money. If you want to keep them under control, plant them in a container or you can dig up a few in mid-summer after they have flowered and died back.
Spring flowering bulbs like crocuses, daffodils and tulips need to be planted in autumn. It’s best to plant crocuses and daffodils at the end of September while tulips need to be planted in November.
Grape hyacinths will arrive in March if the weather is warm enough. The sunshine lights up the little blue flower spikes, wrapped in spiky green leaves. These grow best in bunches and they will also spread and naturalise in any garden so plant a handful and watch them arrive faithfully year after year. Grape hyacinths look great in spring vases.
Daffodils are famous for their presence in William Wordsworth’s poetry and the “host of golden daffodils” is achieved by the way they spread underground, creating ever-expanding areas of yellow gorgeousness. Excellent as cut flowers, these are the traditional blooms for Mother’s Day.
Narcissus take their name from the vain Greek god who stared in the water to see his reflection and was transformed into the narcissus flower. They have a vibrant orange centre, which differentiates them from the daffodil. Often called Jonquils in Australia, these bulbs grow well with daffodils to create a fabulous spring display.
Tulips first grew in the Netherlands and they have been bred to produce blooms of every colour imaginable, providing our April and May vases with elegant flower heads. Any visitor to the tulip fields in Holland will never forget the sight of beautiful bulbs which give joy, year after year.
Alliums begin their stem growth in late Spring, arching high in your borders and when early summer arrives, they burst into circular globes of colour ranging from the traditional purple to the newer shades of white and yellow.
Chives, spring onions and garlic
Chives, spring onions and garlic are also flowering bulbs, usually grown to eat. Chive leaves and spring onions greens are delicious chopped into salads or, in the case of onions and garlic, you can dig up the whole bulb to eat. If you allow the flower buds to form, you will have gorgeous purple blooms but it means the bulb won’t thicken up, as all the goodness goes into making seeds.
Bluebells arrive in clusters in May, filling our woodlands with a gorgeous blue carpet. There are two types in the UK, the native bluebell which has smaller flower stems and is protected in woodlands, and the taller Spanish bluebell, with chunkier stems and flowers. Both of them create a carpet of blue in shady areas and they will spread so if you want to contain them, make sure you plant them in pots.
Dutch irises offer an amazing blue and yellow dash to any spring garden, and if the spring is harsh and cold, they may flower even later in early June. They make fabulous cut flowers
Iris bulbs are best planted in late summer to early autumn in an area with well-drained soil. Make sure your chosen area also gets full sun for the best result
Summer flowering bulbs (to plant in spring)
Summer flowering bulbs produce some of the most show-stopping blooms of the year. Plant these bulbs into borders or containers to ensure a riot of colour into summer and early autumn.
Here’s our pick of the best bulbs to plant in spring:
Acidanthera provides your borders with a fantastic leaf cover and dazzling white blooms with dashes of purple. These will continue to flower into the autumn and make great cut flowers.
Crocosmia (also known as montbretia) can bloom as early as August but usually flowers in September, depending on how warm August is. Grown in groups, their cheerful orange flowers can brighten a corner when all the summer blooms have died back. They spread too so dig up a few if you want to contain them.
Gladioli offer the garden or container tall, elegant spikes of blooms on spiky leaf stems. They come in a variety of colours so plan your container or bed with this in mind. They bloom in late July and make excellent cut flowers.
The peace lily is a curious trumpet-shaped bloom that only flowers in white. Allow the foliage to keep growing to feed the bulb after picking the flower.
Lilies produce exotic flowers with drooping stamens and they come in a range of beautiful colours. These are made for flower vases!
Lily bulbs need to be planted in a sheltered area with moist, but well-drained soil. They do best in an area with full sun that is sheltered against the wind. You can plant lilies from early autumn all the way into late spring as long as you can work with the ground. If the ground is frozen in winter, postpone planting until it warms up enough to work with.
Freesias are bulbs whose glorious scent will fill your flower vases when they are in bloom. These flowers attract pollinators in droves.
Liatris are an excellent bulb choice for the back of any flower bed because their flowers are so tall. Their gorgeous foliage makes a fabulous contrast with their purple flowers. They can provide a focal point at the back of a bed or in the centre of a container and they are best grown in groups for full effect. There are some recently developed white Liatris to contrast with the gorgeous purple shades too.
Brodiaea have bell-shaped flowers that arrive in groups, adding a dash of colour to any flower pot. They enjoy bright sunshine and will thrive in either a permanent flower bed or a container.
Ixias are the most unpretentious of bulbs but they have magical leaves, opening up with green and purple shading and a delicate little flower tucked in there. These have a real place in my heart, just for their foliage alone. Gorgeous!
Dahlias are the queens of the early autumn garden, flowering in many colours and shapes. Plant the tubers at least as deep underground as the height of the bulb and cover them generously with earth. They will need mulching in winter to keep the frost from damaging them.
Dahlias are best grown in an area with full sun and moist but well-drained soil. You can plant them in spring and expect to see flowers from late summer into autumn.
Autumn flowering bulbs (to plant in summer)
Bulbs that flower in autumn should be planted in late summer. These include nerines, autumn crocuses and adaptable cyclamen. These bulbs bring welcome blooms when the flowers of summer are over and will persist into early winter before fading away.
Often considered a spring flower, there are many types of crocus that flower in autumn. The flowers develop from corms which should be planted in late summer or early autumn. The flowers are delicate so position them in a sheltered spot.
Cyclamen hederifolium opens its pretty petals from August and the blooms will last into winter. These hardy plants add glorious splashes of colour to pots and under larger plants.
Nerines are the most exotic bulbs, which will surprise and delight you when other flowers are dying off. Its delicate pink petals stand proud on tall straight stems and I never pick them, just let them thrive in the garden when summer has departed.
Aftercare For Bulbs
Once your bulbs have flowered, you can cut the dead flower stalk away, but leave the green foliage intact. The foliage will continue to photosynthesise which in turn produces plant carbohydrates that get stored in the bulb. If you cut the leaves early, the bulb won’t have enough energy to resprout next season.
Spring bulbs that require chilling can be dug up and stored as soon as the foliage has faded. You can keep these in a fridge until the next planting season. If you live in a very cold climate, you can leave these bulbs in the ground. They will return year after year and even multiply.
Summer bulbs can be dug up and stored after their foliage has faded. Most of these bulbs aren’t cold-hardy so need protection. If you want to leave them in the soil, cover them with a layer of mulch to insolate and protect them.
To dig up bulbs, cut any remaining foliage back to a few centimetres above the ground. Dig up the bulb and shake off as much soil as you can. Place the bulbs on newspaper in a shady area to dry for a few days.
Some bulbs are poisonous so keep all bulbs out of reach of children and animals. Once dry, store them in a paper or mesh bag. If you’re worried they’ll dry out too much, you can add a bit of damp vermiculite to provide a little moisture.
Store bulbs in a dark, dry location with a temperature between10-15.5°C. A garage or garden shed is ideal. Make sure to check them regularly for any signs of mould or decay.
Tips for planting and caring for bulbs
- Plant your bulbs in the same season you buy them. Bulbs are usually sold in the season they should be planted to make it easier for the buyers.
- Never store your bulbs in the same fridge as fruits such as apples. These produce ethylene gas that can kill the plant inside the bulb.
- If possible, keep your soil pH between 6 and 7. This produces more vibrant flower colours.
- If you decide to leave your bulbs in the ground, mark the area so you don’t accidentally dig them up while they are dormant.
- Never store your bulbs in plastic containers. They need to breathe to avoid problems such as mould growth. A mesh bag works well or you can store them in a box filled with sand.
When is the best time to plant bulbs?
Winter flowering bulbs need to get into the ground in late summer to give them time to grow good root systems but you can continue to plant bulbs in autumn too.
Spring and summer flowering bulbs are best planted the previous autumn but some, like dahlias, dislike the frost, so these can be planted in late spring after the risk of frost is over. If left in the ground over winter, they will need a thick mulch to protect them.
What is the best way to plant bulbs?
- First, dig over the area, remove any perennial weeds and add a general fertiliser to the soil.
- As a general rule, plant the bulb twice as deep as the size of the bulb. Allow a bulb’s width between bulbs.
- Use a bulb planter to make this easier, especially if you are planting a lot of bulbs at the same time.
- Remember that the spiky top part of the bulb will become the green foliage and the flatter part is where the roots form. So plant the spiky part upwards towards the sky.
- Water them in generously and then leave them to grow, watering every week or so in dry periods.
The best compost for bulbs
It’s important to find a compost that’s specifically made for bulbs. Bulbs require well-drained and aerated soil and compost for them to thrive. Compost for bulbs is usually quite fibrous to help with drainage.
You can either make your own compost or buy ready-made ones:
Home-made bulb compost
Mix one part compost with one part horticulture grit. You can also mulch the top of the soil with course manure mulch. Add a bit of blood, fish and bone meal to the mix for extra nutrients.
Commercial mixes are ready-made for you. You don’t need to worry about getting the combinations right, you can simply use it as is. This type of mix will work for most bulbs and will help to prevent bulb rot.
When to plant spring bulbs
The best time to plant spring bulbs is in Autumn. This will give them time to become established before winter hits.
When to plant crocus bulbs
This will depend on the type of crocus you plan on planting. Autumn crocuses need to be planted in late summer while spring crocuses should be planted in Autumn.
Should you soak bulbs before planting?
No, it’s not required to soak bulbs before planting. Some adaptions like tubers need soaking, however, so make sure you know what you’re dealing with. If you want to speed up the sprouting process, you can soak them for 12 to 24 hours before planting.