There is a myth, probably born in heat & nurtured in the longing for shade & leisure, that there “isn’t much to do” in the garden in the heat of summer. There is another, born more respectably of summer’s flat light, that the garden itself is dull.
Alas (in one case) and fortunately (in another) both are
myths: the summer garden has much to offer in way of work and beauty. Let’s start with chores. Do them early in the day, promising yourself some time in the shade, with your beverage of choice to follow as a reward for your hard work.
Generally, you have still got to keep weeding, but it’s time to stop feeding. By the end of the month, you don’t want to encourage new sappy growth. Winter is not coming soon, but it is coming. You want all your plants to be aware of this change: allow berries to form, allow growth to harden. In each department specifically:
Keep well hydrated, but intelligently. When you water a plant that has good drainage, and it has dried out 4 inches below the surface, water it well around the dripline and you will be carrying oxygen to the roots along with water. If drainage is bad, the roots sit in water and the plant drowns. If you water too briefly, the plant maintains a shallow root system and the need for water is increased. Trees with shallow roots are also more vulnerable to wind. So, in sum: ensure good drainage from the beginning, then water infrequently but deeply (at least 8-12" into the ground).
Mid Summer is also a good time to prune several fruit and ornamental trees. There is a kind of secondary dormancy that sets in during the heat, and difficult trees like Japanese maples can be thinned and shaped without difficulty as long as the temperature is not above 27C.
In the shrub garden, roses should be pruned for the last time in August to encourage new growth. After this pruning, you must leave them alone to form hips. Rosehips are nature's way of saying to the plant: winter is coming, enough with the new growth. A rose hardened off in this way will survive much better than one that keeps trying to throw out sappy growth.
Hydrangeas will be performing their yearly colour change. Some people like to nip the top flowers to encourage more shoots from the sides on the “repeat” varieties. On the other hand, the maturation of that flower urges the plant to form strong growth for the coming year.
In general, it is better to leave shrubs alone at this time, the urge to be too tidy can lead to winter death.
However, yew and boxwood hedges should be trimmed now to encourage the formation of dense growth. It is also a good idea to do a good shearing of cedar hedges at this time.
In the perennial garden, it is time to divide iris and peonies to share. They too enter a dormant period in July and August, and it is not difficult to lift them and break off pieces of rhizome or root to create new plants for your friends. Broken roots of poppies will also regenerate surprisingly quickly if planted at one.
It is also a good thing to deadhead or shear back perennials. You will often get a small rebloom in the summer, but don't go crazy, cutting them back to nothing: remember here too that sappy growth is dangerous when the cold comes in fall. Luckily here in the lower mainland, the real cold doesn't typically arrive until December and January, so these cautions only apply in October or so.
It is the time when many bulbs come on sale at local nurseries. Plants such as daffodils, hyacinths, tulips, crocus and many more. Try to get to them, and get them planted, as soon as possible. Some bulbs (notoriously snowdrops) really loathe being dried out, and the sooner you can get them in the ground, the better.
In drought & heat, reserve water for gardens. Lawns cope with heat by going brown & rebound as soon as rains start. Heaven knows we have a LOT of rain. Once it starts, you can mow, but leave lawn clippings on surface to nourish the growing grass.
On the bright side - Hardy fuchsias are still going strong, hibiscus & buddleia are holding their own, and of course, there are roses, whose wonderful fragrance we can enjoy. It is a long time before autumn will start to turn the colour of the leaves and lay a frigid hand on the garden.
Having done your self-assigned chores in the morning, you now have a chance to sit on the deck, gaze upon with pleasure and enjoy the fruits of your labour.