Reviving Late-Summer Flowers

Rosa 'Perfume Delight' 2 JaKMPM
Despite the high heat here in the Pacific Northwest, the roses have done well. (photo by Jessie Keith)

Perhaps we have been through the “dog days of summer” here in the Pacific Northwest with our daytime temperatures reaching 90+ degrees. Not only have those of us without air conditioning suffered, but many of our plants did as well.

In my own garden, I had plants that were very wilted during these hot afternoons, and yet I knew the plants did not need watering. The soil was moist, but it was just too hot for the plants to take up the amount of water they needed. They were transpiring more water from their leaves than they could absorb. A quick fix that I often used on hot afternoons was to spray the foliage of wilted leaves with water, and that would usually revive them. While this is not a long term fix, it does work temporarily and usually one spraying with water in the afternoon would keep the plants from wilting that day.

My Digiplexus with blooms that need to be cut.
My Digiplexus with blooms that need to be cut.

Cut Back Old Flowers

A new plant for me this year was Digiplexis ‘Illumination Flame’, and it performed magnificently all during the months of June and July. It produced tall stately stems of light brown and rose colored flowers and was a favorite of hummingbirds. As I removed some of the old stems, I noticed in a short time that there were new stems emerging from where I made the cut. I left some of the flower stems on the plants, even though there were only blooms at the top, as I wanted garden visitors to see this new plant with some flowers. However, it is now time to remove the stems, and fertilize the plant with rose fertilizer to encourage new growth and new flowers. Many annual plants, like zinnias, cosmos, cleome, and salvia, to name a few, would benefit from the same procedure. Carefully remove the old flower stems and then fertilize. Be especially careful with salvia as the stems are quite fragile and easily break.

Amend Soils

On a recent visit to a local garden center, I noticed that they have many annuals in gallon-size containers that were in full bloom. If you have some empty spaces in your flower beds, an addition of some new blooming plants can provide instant color. Using Black Gold Waterhold Cocoblend Potting Soil would be a good addition at this time of year to help the soil around these new plants retain moisture. With a few days of regular watering, these new plants will look as though they have been in your garden beds all summer!

Remove Old Foliage

In addition to the tired look of some plants, with the hot sun that we have had, there were plants in my garden that had leaves that were actually burnt by the sun. The leaves scorched in spite of the fact that I was giving the plants extra water. My large Gunnera leaves scorched even though the plant is in the shade, it had plenty of water, and I sprayed the leaves several times during the hot sunny days. Some of my container plants that are sun-loving could not take the afternoon heat and their leaves scorched, too. It surprised me that this happened on some Cannas; in the many years I have grown them, I have never seen their leaves scorched by the sun. I have since added Black Gold Just Coir as mulch in some of my containers to give the soil some additional moisture-retaining capability.

Some plants with heat and sun sensitivities have developed scorched leaves, like this Gunnera.
Some plants, like this Gunnera, have heat and sun sensitivities that cause them to develop scorched leaves when temperatures rise.


Roses have generally thrived throughout this season. On a recent visit to the International Rose Test Garden at Portland’s Washington Park, I do not recall ever seeing such an array of color during the summer. With adequate water and removing the old flower stems, roses can provide a continuous show of color even in heat. This is the time to add a final application of rose fertilizer as mid-August is generally recognized as the time for the final application of fertilizer for the year.

Late summer is a good time to walk through the garden and take notes on plants that have thrived and those that have not. Then make additions or deletions as necessary. I think every gardener learns something new about plants and their own garden every year. Whereas a gardener might wishfully think the garden is complete, it never is. The garden is constantly evolving as we as gardeners are also evolving. As many gardeners would say: “There is always room for another plant”!

About Mike Darcy

Mike lives and gardens in a suburb of Portland, Oregon where he has resided since 1969. He grew in up Tucson, Arizona where he worked at a small retail nursery during his high school and college years. He received his formal education at the University of Arizona where he was awarded a Bachelor of Science Degree in Horticulture, and though he values his formal education, he values his field-experience more. It is hard to beat the ‘hands on’ experience of actually gardening, visiting gardens, and sharing information with other gardeners. Mike has been involved with gardening communications throughout his adult life. In addition to garden writing, he has done television gardening shows in Portland, and for over 30 years he hosted a Saturday radio talk show in Portland. Now he writes, speaks, gardens and continues to share his love of gardening. To be connected to the gardening industry is a bonus in life for Mike. He has found gardeners to be among the friendliest and most caring, generous people. Consequently, many of his friends he has met through gardening.

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