An expert guide to summer bulbs: what to plant, when to grow, and where to buy

·6-min read
summer bulbs
Summer bulbs guide: when to plant & what to growJacky Parker Photography - Getty Images

So, you're searching the web for answers about your summer bulbs. Why bulbs? Well, as horticulturalist expert at Miracle-Gro Kate Turner explains, bulbs are a fantastic and economical way to provide wonderful colour and fabulous scent to your garden all year round.

We bought you front garden ideas, how to grow your own vegetable garden, and how to make the most of small outdoor spaces: next up, your complete guide to summer bulbs.

Our expert-led guide covers what bulbs to plant, when to sow them, how to sow them, and when they flower, plus what care the many different types need.

Only got room on your balcony for pots? We've even covered which bulbs do best in pots, too.

summer bulbs
Betsie Van der Meer - Getty Images

Your complete guide to summer bulbs

If you've got questions about anything summer bulb related, you're in the right place.

What's the difference between spring and summer bulbs?

Good question. The clue's in the name with this one really - spring bulbs flower in the spring, and summer bulbs flower in the summer.

You don't want to mix them up as, if you do, your bulbs may not flower at all as they'll be exposed to the wrong growing conditions.

Tom Clarke, head gardener at Exbury Gardens in the New Forest, shares that there's a common misconception that spring is the only time of the year to bloom bulbs in your garden. "There are some wonderful summer-flowering bulbs that you can plant, and there are some easy tricks to make sure you make the most of their scent and structure," he shares.

summer bulbs
Jacky Parker Photography - Getty Images

The best summer bulbs: how to choose

According to BBC TV gardener and landscape designer Mark Lane, when it comes to summer bulbs, there are many to choose from.

"Summer bulbs span tubers, corms and rhizomes. My top five are dahlias, lilies, eucomis, crocosmia and begonia," he shares.

Alongside those, there are also the lactiflora varieties of peony, agapanthus, gladioli, nerine for late summer and early autumn, as well as canna and Zantedeschia, he explains.

Tom's top bulb choices for scent are lilies and freesias; for structure, alliums and agapanthus; and for show-off blooms, gladioli and begonias, which are officially tubers, he adds.

A handy little list of summer bulbs:

  • Dahlias

  • Lilies

  • Eucomis

  • Crocosmia

  • Begonia

  • Peonu

  • Agapanthus

  • Gladioli

  • Nerine

  • Canna

  • Zantedeschia

  • Freezias

  • Alliums

  • Polianthes

Where to plant my summer bulbs

The majority of summer bulbs are sun worshipers, so Mark recommends planting them in full sun. "If you're working with a shady garden, balcony or patio area, begonias will grow in partial shade, as will martagon lilies," he shares.

Other than that, the requirements will differ from bulb to bulb. Generally speaking, summer bulbs prefer warm and sunny.

Do make sure you're planting in free-draining soil too - you don't want any of your bulbs rotting.

When to plant summer bulbs

You've learnt that spring bulbs bloom in spring, and summer bulbs in summer, but when should you plant them both?

"Whereas spring bulbs, such as crocus, narcissus, muscari and tulip, are planted in the autumn and flower in the spring, summer bulbs are planted in the spring once the soil is beginning to warm up," explains Mark.

If you find it hard to remember, think of this: summer bulbs come from hot climates, and therefore need a minimum of 13 degrees celsius to start to grow. "A great way of remembering? Summer bulbs get planted at the same time your tomatoes go outdoors," Mark explains.

Fun fact: you can actually plant the hardy summer flowering bulbs such as lilies and crocosmia in the autumn, shares Kate. "Less hardy varieties, such as gladiolis and begonias, must only be planted outside when all risk of frost has passed in late spring or, if you're keen to get going, they can be potted indoors in mid-spring and moved outside when the weather warms up," she explains.

Got it?

How to plant summer bulbs

According to Tom, it's very straightforward. You're simply planting bulbs into the ground, but here’s a step-by-step guide from the gardener, for your reference.

  1. Plant the bulb with its tip pointing upwards and roots pointing down. This may seem obvious, but it’s not always easy to tell which end of a bulb is which. If you can’t tell the tip from the roots, plant the bulb on its side and it will find its own way.

  2. A rule of thumb with planting bulbs is to plant them twice the depth of the bulb.

  3. Most bulbs prefer a well-drained fertile soil but always add a handful of grit to the hole before dropping in the bulb. If your soil is very wet and heavy, consider planting bulbs in pots rather than in the ground.

  4. Fill in the hole and compact gently.

Remember this: as a general rule of thumb, plant summer bulbs about three times their depth into a mix of sharp sand and good peat-free compost. Decent drainage is key.

Top tips from Mark: If you want to get a head start on summer you can grow summer bulbs indoors in a greenhouse, conservatory or warm porch a month or two before transplanting outdoors.

"If you do this with dahlias, you can take basal cuttings during the spring from the new growth and increase your stock for free - but please always check for plant breeder’s rights," he shares.

summer bulbs
Photography by Gordana Adamovic Mladenovic - Getty Images

When do summer bulbs flower?

It'll depend from bulb to bulb, but largely, they'll flower across the summer months, which gives you plenty to look forward too.

How to grow summer bulbs: care and upkeep

Again, it'll vary from flower to flower, so always read the packet as it'll give you clear instruction on how to plant and care for your bulb.

Mark and Tom both advise watering regularly, as you would do for any other flowering plant, but being mindful not to overwater and drown the bulbs. As above, they're prone to rotting, and it's a fine line.

Once your bulbs are blooming, aim to water around three times a week.

Which summer bulbs do best in pots?

Not got much space but still keen to get planting?

Funnily enough, summer bulbs actually do best when planted in pots, so you're in luck. "All of the summer bulbs mentioned above are perfect for growing in pots and containers," shares Mark.

He goes on to add that agapanthus, in particular, flowers best when its roots are constricted. "Agapanthus grow on rocky outcrops in South Africa, so by adding horticultural grit or sand into peat-free multi-purpose compost, it will help with drainage, just like the rocks and natural environment from its native origin."

Not sure how to plant in a pot? Let Tom's tips help.

  1. Choose pots with good drainage holes.

  2. Place a few crocks (pieces of broken pottery) in the bottom of the pot to stop drainage holes clogging up with compost.

  3. Raise pots on pot feet in winter to improve drainage

Happy gardening.

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