Updated: Nov 7, 2021
June sees the start of summer and, by now, plants in the garden should be growing strongly and daily tasks have morphed from sowing seeds and planting out to managing the garden's occupants - both the plants and the pests. If it is hot then irrigation is vital and if it is wet then weeding and grass cutting seem endless because the warmer weather encourages so much more growth. Here are some of the things which need doing in June:
Bearded irises will have finished flowering. Once they have flowered they enter a period of semi-dormancy when the leaves brown and growth stops. This is the time to trim the leaves back to between about 10 to 15 cm in length and clear the ground around them of weeds - at the same time stripping away any dead leaves completely and making sure that the rhizome (the swollen base of the plant) is as exposed to the sun as possible. The rhizomes need to bask in the sun if they are to flower well next year. If your clump of irises is congested then dig them all up and replant some of them elsewhere. It is a great time to increase your stock of favourite irises and either give some away or swap them with friends. Simply separate a section of iris rhizome with roots and shoots (they snap in two easily) and replant with the rhizome only partially buried in the soil and facing towards the sun.
Most roses will be peaking by early June and they should be fed with a balanced plant food (tomato food is fine). Unless you are growing a rose for its autumn hips then deadhead it after flowering to encourage more flowers and pick off leaves that have black spot and destroy them. Don't compost the diseased leaves as you will introduce the fungus into the compost heap. Roses also like water, so irrigate well in dry periods.
This reliable rose is called Sally Holmes - and producing this number of flowers takes energy. Providing the plant is fed after the first flush of flowers, the dead flower clusters are cut well back and the plant is watered if necessary, it will continue to flower all summer - although not to this extent:
Deadhead perennials and flowering annual plants such as cosmos - remove flowers to encourage further flowering. Once a perennial sets seed it has done its job and can stop flowering - so do not allow seed heads to develop unless you specifically want to collect the seeds or leave them on the plant as bird food or for decorative purposes.
Watch out for lily beetles - If you grow lilies, either in pots or in the ground, then check them daily for lily beetle damage. These pests eat the leaves and can quickly denude a plant. They have a brilliant strategy for outwitting you. The beetle has a bright red carapace. This makes it look fierce to some predators but also makes it too easy to spot as far as others are concerned (e.g. us). Once you have spotted a lily beetle on a leaf you need to pick it off the leaf firmly and quickly - I grasp them in a folded leaf I have got from elsewhere and then squash the beetle to kill it. If you delay or give the beetle too much warning it will hurl itself off the leaf, turning upside down as it falls and landing in the soil on its back. The underside of the beetle is the same colour as soil - so you can't find it.
Keep tying in climbing plants as they grow so that they are supported if there are strong winds or heavy rain/hail. In the picture below you see Rosa moyesii Geranium, which only flowers once but has superb red hips in the autumn. To prolong the season we grow a viticella clematis called Etoile Violette next to the rose and encourage it to climb through the rose - which it does happily, even escaping into the adjacent cherry tree given half a chance. Even though it is self supporting we need to tie it in the encourage it to grow in the direction we want.
In the vegetable garden sow successions of salads and vegetables such as rocket, beans, peas, beetroot and radishes so that you have a steady supply. When you are ready to remove bean or pea plants which are spent DO NOT pull them out. Cut the above ground growth off and compost it. Dig the roots of beans and peas into the earth. The roots of leguminous plants have a unique capacity to fix nitrogen into the soil. I will go into more detail about this in a future blog.
Sow the seeds of winter vegetables such as leeks, chard and cavalo nero and other brassicas.
In the fruit garden soft fruit - red, white and black currants, raspberries, gooseberries and tayberries - will be ripening now. Once you have picked and stored the fruit you can prune the plants if you have time now. Otherwise it can wait until the winter. It is important to know that there are two types of raspberry - some fruit on last year's growth. These fruit only once and once they have fruited you can cut back the now redundant shoots making certain that you do not also cut back the young growth as this will carry next year's raspberries. The other type fruits on this year's growth. This fruits later in the summer and can continue to provide you with raspberries until the autumn. With this version, in the autumn/winter you cut the old grown back to the ground completely and in the spring new growth emerges. It is important not to get the two types mixed up.
And of course the inevitable - cutting the grass regularly (you can now mow where you had daffodils naturalising in the grass or where you had a spring meadow), weeding and irrigating.