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Late flowering Perennials
Dianne and Gary Westlake
Peterborough and Area Master Gardeners
At this time of the year many gardeners tend to feel that they are entering the last stages of a marathon. From the beginning of the growing season when the first spring bulb emerges from the frozen earth to end when the last tool is stored for the winter, our gardens change. This time of the year can be a challenge as colour and interest can be difficult to maintain into the fall. But you do not have to rely on only you pots and annuals. Take a look at what is blooming in other gardens at this time of the year and you will find many options. Many gardens tend be at their best during one season. Some have a burst of colour in spring with their bulbs and flowering shrubs. Others peak in summer with their beautiful daylilies and peonies. The goal for many is to have continuous interest throughout the season. Echinacea or Purple Cone Flower tends to be a tall, sturdy plant native plant. We are seeing more and more varieties on the market that have been hybridized to bring out specific traits. At one time the varieties tended to provide different shades of pink and white but now we are finding colours ranging from bright orange to yellow and even green. The flower heads can be different shapes with multiple petals, almost like pom poms. Even the height of the flower stalks vary from 45 cm to more than 1.5 metres. In our garden, some of the varieties with the fancy heads require some assistance to keep them upright. Leave the seed heads in the fall. The birds will love them but be aware that there may be a number of seedlings in the spring. When you see a clump of brilliant yellow or orange in a flower bed, you are probably seeing Rudbeckia. This strong grower is easy care and will take dry conditions. The only drawback we have seen is the tendency to self seed. Deadheading can solve this issue. Joe Pye Weed can grow to 1.5 metres. It has strong stems and pink flowers that are a favourite of butterflies. It does tend to spread once it is established but can be controlled fairly easily by dividing in the spring. Sedums come in a variety of sizes and foliage colour but the ones that are of greatest interest at this time are the taller varieties. Autumn Joy is a favourite that is dependable but there are many more varieties that provide alternatives in foliage colour (from variegated to deep purple) and flower colour (white to deep pink and purple). Hostas are still in bloom. One variety, Red October, even flowers later in the season (October) and has red stems. Leadwort (Ceratostigma plumbaginoides ) is a ground cover that has beautiful blue flowers. It likes well drained soil and tends to spread so be careful about the placement. We have resorted to putting it in a large pot because it tends to expand to readily. Hydrangea is a late blooming shrub. Some varieties begin to bloom earlier in the summer but the flowers will remain in good condition later in the season. They can even be dried and used inside in your arrangements. Other varieties are in full bloom and will provide colour for many more weeks. Hardy Hibiscus are herbaceous (they die back to ground each season) and have huge blooms, often the size of a dinner plates. Rose of Sharon is a shrub and flowers in August and into September. Their flowers tend to range from white to pink and the shrub itself has attractive foliage. It is a bit tender here and can be lost in a severe winter. Monkshood (Aconitum) is one plant to be used with caution. All parts are poisonous. The flowers are a beautiful blue and the plants stand about 1.5 metres. Toad lily (Tricyrtis) is an odd looking plant with speckled flowers. It is a small plant and needs to be placed close to a path to enjoy it. Ornamental Grasses are standing tall and in flower. Many varieties are clumping and will add interest throughout the winter. The birds will benefit as well. Now is the time to plan for next year’s show and it is not too late to plant perennials. The plants will have plenty of time to establish their root systems prior to freeze up and you will be rewarded with lots of colour. This is the time to look in garden centres and save on discounted plants. Also look for horticultural societies’ fall plant sales. Peterborough Horticultural Society will be holding its plant sale on September 19th at St. Alban’s Church. Previously published in the Peterborough Examiner

Source: http://www.peterboroughgardens.ca/mg_articles/Late%20flowering%20Perennials%20-%20Dianne%20and%20Gary.pdf