JUNE 2025

This month generally brings with it a greater certainty of warmer and sunnier weather. That said as I write this I’m wearing a scarf and it’s pouring with rain! Hopefully by the end of the month the temperatures will have picked up because it is now that you want to start planting the tender and more temporary plants outdoors.

These are plants that include particular vegetables, which require plenty of warmth. Also half-hardy annuals and tender perennials that will live many years so long as they have protection from the cold.

Starting with the vegetable plants this month is the time to put out the squash/ pumpkins, courgettes and sweetcorn. Our crops of tomatoes, cucumbers, melons, aubergines and chilli peppers we grow under glass as this ensures high temperatures, but these crops can all be grown outdoors so long as all risk of frost has passed. If exposed to the cold many of these plants will either slump and not grow to their full strength or may die. With high temperatures these plants will thrive.

Half-hardy annuals originate in warmer parts of the world. They are plants that have evolved to take advantage of brief rain showers over more usually parched landscapes such as the African plains. Following the rains the seedlings must germinate, attract pollinators, and produce seed in a brief window. The seed is then dropped, and waits out the dry periods before the next rains come. These are plants that produce brightly coloured flowers over a short period of time making them useful to fill gaps, give impact, and create a changing display. Think of flowers such as Cosmos, Cleome, Tagates, Zinnias and Ageratum.

These plants are best sown as seeds indoors/under cover to ensure sufficient heat for germination. Once they have bulked out they are strong enough, and ready to be planted outdoors.

We come finally to the tender perennial plants. Some such as Osteospermum, Impatiens and Gazanias are often treated as half-hardy annuals. Cuttings or seeds are collected at the end of the season for use the following year, and the main plants are composted. Others may be removed from containers or the ground and overwintered before being put out again for the summer. Heliotropes and Pelargoniums are good examples of plants that are treated in this way, and kept from year to year.

The tender perennials tend to be a little tougher than the half-hardy annuals, and many of ours have been outdoors for the last few weeks. Now as the temperatures warm those remaining few plants clinging to the indoor warmth can find their spots outdoors. They should enjoy a good few months before they return to the cover of the glass.