As fall approaches, many gardeners (and not just newly minted ones) get the doldrums. Between the heat, humidity and drought, it becomes awfully tempting to turn our backs on the garden.
But I think that’s really too bad. In Canada, the growing season is short enough, so why quit when there are weeks of nice weather ahead? With its cooler temperatures and golden light, late summer and autumn can offer some of the most beautiful and enjoyable times in the garden. Here are a few tips to perk up your patch and extend your flower show well into fall.
Deadhead to encourage more blooms
By late summer, many early-blooming perennials are setting seed, flopping over and generally looking untidy, so a grooming session is in order. The first step is to deadhead, which means removing faded flowers and seed heads. This will promote a second and longer flowering period for many perennials, such as tickseed (Coreopsis), shasta daisy (Leucanthemum x superbum) and speedwell (Veronica spp.), as well as most modern rose cultivars.
Trim away old foliage
Remove tattered or sunburned foliage and cut back excess growth that’s crowding out other plants. Certain perennials, such as lady’s mantle (Alchemilla mollis) and some cranesbills (including ‘Wargrave Pink’ geranium, Geranium x oxonianum ‘Wargrave Pink’), have a fresh crop of leaves hiding under their mature foliage. Other early bloomers, including pinks (Dianthus spp.), catmint(Nepeta spp.) and lavender can be tidied by cutting back the foliage by half with hedge shears. And don’t forget to clear out weeds before they have a chance to set seed.
Hydrate your beds
Give your garden a deep, refreshing drink once a week during dry periods with at least 25 millimetres of water. To measure, set an empty tuna can, or the like, under your sprinkler. Water early in the morning so you don’t waste any through evaporation.
Add some late bloomers
If there are little or no colourful flowers left in the garden, add more late-season perennials. There are plenty of tough plants that reach their peak bloom in late summer (the bonus is that many attract butterflies). Most are North American prairie natives, such as coneflowers(Echinacea spp.) and black-eyed Susans (Rudbeckia spp.) or their cultivars.
Container-grown perennials from the nursery can be planted any time during the summer. It’s important to water regularly (at least once a week) to help roots get established; don’t let plants dry out.
Fill in holes with fall annuals
For more late-summer colour, fill gaps with traditional fall annuals such as chrysanthemums (which are really perennials, treated as annuals), pansies and ornamental kale.
Replace pooped-out container displays with fresh fall plantings. Some to try: Mexican feather grass (Nassella tenuissima), African daisies (Osteospermum), golden creeping Jenny (Lysimachia nummularia ‘Aurea’) and snapdragons.
- Japanese anemone (Anemone x hybrida) full sun to part shade Zone 4
- Michaelmas daisy (Aster novi-belgii) full sun
- Purple coneflower (Echinacea purpurea) full sun
- ‘Gateway’ Joe Pye weed (Eupatorium purpureum ssp. maculatum ‘Gateway’) full sun
- Sneezeweed (Helenium autumnale) full sun
- False sunflower (Heliopsis) full sun
- Prairie blazing star (Liatris pycnostachya) full sun
- Oriental lily hybrids and Orienpet (Oriental-Trumpet cross) lillies, full sun
- Russian sage (Perovskia atriplicifolia) full sun
- ‘Herbstsonne’ and ‘Goldquelle’ Autumn sun coneflowers (Rudbeckia nitida ‘Herbstsonne’ and ‘Goldquelle’) full sun
- Autumn Joy sedum (Sedum ‘Herbstfreude’) full sun
- ‘Matrona’ sedum (S. telephium ‘Matrona’) full sun
- Culver’s root (Veronicastrum virginicum syn. Veronica virginica) full sun to part shade
- Feather reed grass (Calamagrostis x acutiflora ‘Karl Foerster’) full sun
- ‘Transparent’ and ‘Skyracer’ tall purple moor grasses (Molinia caerulea ssp. arundinacea‘Skyracer’ and ‘Transparent’) full sun
- Switch grass (Panicum virgatum cvs.) full sun
- Fountain grass (Pennisetum alopecuroides) full sun
- Scotch heather (Calluna vulgaris cvs.) full sun
- Blue mist spirea (Caryopteris x clandonensis cvs.) full sun to part shade
- PeeGee hydrangea (Hydrangea paniculata ‘Grandiflora’) full sun to part shade
- Oakleaf hydrangea (H. quercifolia) full sun to part shade