Flowers to plant and sow in May

Flowers to plant and sow in May

John, Passionate gardener, Cambridge

Guide written by:

John, Passionate gardener, Cambridge

61 guides

May is a critical month in the garden – if you want beautiful blooms all summer, you have to put in the work now! Planting potted flowers provides quicker results but there's still time to sow some varieties. From flowerbeds to hedges, pots to climbing plants, read on to find out which flowers to plant and sow in May.

Important features

  • Pots and planters
  • Hedge plants
  • Flowerbeds
  • Climbing plants
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Preparing flowerbeds for summer


While it's usually best to sow your flower seeds at the start of spring, it's not too late too do so now and you'll still get blooms throughout the summer! In fact, if the weather has been particularly cold, May can actually be the ideal time to get your flowers started.

There are many fast-growing flower seeds to sow in May including cosmos, clarkia, California poppies (and other varieties), love-in-a-mists, snapdragons, Mexican marigolds, cornflowers, alyssum and morning glories.

Be sure to choose a warm spot with plenty of sunlight for cold-sensitive varieties such as nasturtiums. If you want to get a little bit ahead, you can always plant out shop-bought flowers or seedlings that you've already started indoors.

If you purchased zinnias and or perennials like tickseed, beeblossom or peonies in containers, now is the time to plant them in the ground. The same goes for lily of the valley purchased in pots: as soon as the flowers wilt, you can pop them in a partially shaded spot in the garden. If you keep them well-protected, you can count on their pretty blooms appearing every year by the 1st of May!

Summer-flowering bulbs, such as begonias, dahlias, cannas, irises and gladioli, can also be planted. Pull out any spring bulbs that have finished flowering and store them in slightly damp sand for replanting in future.

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Climbing plants in May


Nothing beats a good climbing plant to cover an unsightly wall, balcony rail, trellis or fence. What's more, there's no end of varieties including:

  • honeysuckle;
  • passionflower;
  • climbing nasturtium;
  • jasmine;
  • clockvines;
  • and cobaea scandens (or cathedral bells).

A budget-friendly way to get more volume from climbing plants is to simply divide your plants.

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Indoor plant care in May


A lot of indoor plants will benefit from some time outdoors provided the weather is nice enough.

As soon as the last frost is out of the way, your indoor plants can enjoy a bit of fresh air in a sheltered spot away from the sun and wind. A patio or porch will usually provide the ideal location and hardy plants should be okay outdoors until the beginning of autumn. Among some of the plants that can be moved outdoors are azaleas, begonia rex, anthurium and boat orchids.

Oleanders, cactus and other succulents can also go outdoors, provided you expose them gradually to the sunlight. If you can't move your plants around easily, you can always air out your conservatory or greenhouse in good weather.

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Pond plants in May


Garden ponds also 'spring' back into life around this time of year. If you have bought things like water lilies, horsetails and pickerelweed in containers, you can now plant them out in pond baskets.

You can also take cuttings from your water lilies by trimming around 10 cm sections from the rhizome making sure each cutting has at least one bud.

Plant out yellow irises, arrowheads, bogbean, water chestnuts and paper reeds at the end of the month. Finally, you can always give your pond border an exotic twist with a few white Ethiopian arums.

Potted flowers for balconies and patios


Many of the annual, perennial, climbing and bulb-grown flowers discussed above can also be grown effectively in pots or planters. If you have a spot with full sun, you can put in ivy geraniums, petunias, Mexican marigolds, zinnias and tobacco plants. In terms of summer-flowering bulbs, go for things like dwarf dahlias, freesias, crocosmia and polyanthus.

In areas with part shade, trailing begonias, lobelias, fuchsias and touch-me-nots should do well. If you have the space for larger raised beds, you can pick varieties like oleander or even citrus trees. If you really want to go all out, why not invest in a dwarf palm or banana plant for a tropical vibe?

Planting in pots gives you the opportunity to let your imagination and creativity run free. Why not try pairing different colours and varieties in the same container? Mix up classic geraniums with things like lobelias, twinspur, everlasting flowers, petunias, morning glories or ageratum.

But flowers needn't be the only decorative elements in your garden: plants like coleus or solenostemon also feature interesting foliage.

Bear in mind that your choice of pots and planters will also impact your floral compositions. You'll have to choose the right size and shape of containers for your plants. In terms of material, solid sandstone, raw earthenware or coloured plastic are just a few of the options.

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Pots and planters

Floral hedges for summer


May is a great time for planting flowering shrubs to make up hedges that will flood your garden with flowers from summer onwards. However, don't forget to water them regularly in their first year and mulch using grass clippings, leaves, ferns or compost to help the soil retain moisture.

Here's a list of eight flowering shrubs that you might want to try out:

  • Mexican orange blossom;
  • meadowsweets;
  • abelia;
  • caryopteris;
  • Russian sage;
  • summer lilac;
  • hibiscus;
  • summersweet (clethra alnifolia).

Keep in mind that you'll need to space your plants at least 70 cm apart. It's a good idea to fill in the gaps between these plants with varieties such as St John's wort, aster and reed grass.

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Guide written by:

John, Passionate gardener, Cambridge, 61 guides

John, Passionate gardener, Cambridge

When I was young, I was already working in the family garden. Perhaps that is where my interest in plants and gardening came from. So, it was logical for me to study both plant biology and agronomy.   At the request of various publishers I have, over twenty-five years, written many books on the subject of plants and mushrooms (a subject that is close to my heart).They were mostly identification guides at first, but shortly after they were about gardening, thus renewing the first passion of my childhood.   I have also regularly collaborated with several magazines specializing in the field of gardening or more generally in nature. There is no gardener without a garden, I have cultivated mine in a small corner of Cambridge for the last thirty years and this is where I put into practice the methods of cultivation that will I advise you in as well.

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