Rosebie Morton’s May Gardening Guide

If you’re wondering how to get stuck into gardening this month, we’ve got everything you need to know: Rosebie Morton, founder of The Real Flower Company, shares her top tips. Here’s your May gardening guide.

Gardening In May: What To Sow & Grow This Month

The speed that everything grows in May never ceases to amaze me. After the dormancy of winter, followed by a spring awakening, nature suddenly leaps into full overdrive. Whether you’ve sown seeds or you’re planning on nipping down to the local garden centre, May is the month for planting up pots and containers ready for a colourful display all summer long.

How To Create A Colourful Flower Display

Fill your chosen planter with a good multipurpose, peat-free compost mixed with a slow-release fertiliser. Struggling with what plants to use? The simplest rule is to go for three different types of plant: a thriller, a filler and a spiller plant. 

The thriller tends to be the tallest plant in the container. Salvias make a great choice; reliable and floriferous, choose Salvia microphylla Wine and Roses, Peach Melba, or Love and wishes. Cosmos are another dependable option; Cosmos Apollo is a really good compact variety, so ideal for pots. If, like me, you’re besotted with scent, pick Cosmos Chocamocha or Cherry Chocolate.

Summer snapdragon (Angelonia angustifolia) is another great choice – this will brighten up any container with continuous scented flowers in whites, pinks and purples. (And it doesn’t need dead-heading.) Also worthy of consideration is the new compact Dahlia Mystic series, which have beautiful dark foliage and contrasting flower colours.

The spiller plant is what will soften the edges of any container, cascading down over the sides. Textural foliages are ideal for this job; Helichrysum Silver mist or petiolare are both fantastic. For trailing flowers, any Swan river daisies (Brachycomes), Lobelias, Nemesias and trailing Verbenas will all give you the desired effect, obediently providing a waterfall effect over the  containers’ sides. 

Finally, the filler plants. I love putting herbs in as fillers: lavenders, scented pelargoniums such as Attar of Roses or pink Capitatum, and oregano all work well. Mexican fleablane (Erigeron Karvinskianus) is a fabulous filler, as are many types of Verbena. 

Grasses To Plant In Summer

If you’re away for much of the summer and you’re worried about watering, it’s worth considering grasses such as fountain grass (Pennisetum) – these can look very effective in a pot. Pennisetum Fireworks is a stunning variety with pink, red and green heads. Once established, grasses can survive dry conditions. Aeoniums, Echeverias and Sedums planted in shallow containers are also very drought-tolerant, and they look very architecturally attractive.

Can You Plant Sweetpeas In Summer?

Now is the time to be planting out both dahlias and sweetpeas. Both are hungry feeders, so dig good holes for them and put a combination of compost and slow-release fertiliser in the holes before planting. (Ensure the plants are  also well-watered before you plant them.)

Mulch around the plants to maintain moisture and suppress weeds, and watch out for slugs. Give the sweetpeas time to get established before introducing canes for them to grow up.  If space is an issue, dahlias and sweetpeas can be planted in deep pots containing a good rich mix of compost and fertiliser. If they’re kept well-watered and fed, they’ll look fantastic throughout the summer, providing you with copious stems to pick for a vase.