September is the time to evaluate your 2022 gardening fails

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Cape Cod hydrangeas are naturally dwarfed for compact spaces and containers.

Monrovia Nurseries

September means back to school and back to the basics when it comes to yard care.

This is a good month to fertilize the lawn, remove the weeds from garden beds, and refresh your containers and porch pots with fall color.

This is also a good time to review your landscape failures that you can blame on the change in climate. Identify your heat-stressed shrubs (wilting hydrangeas and sun-burned heucheras are on my list) and replace them with heat-hardy plants that can handle life in the hot seat.

Q. Can you please tell me which hydrangeas can take full sun? I know there are some white hydrangeas that like sun but at the nursery I was told that the white hydrangea “Blushing Bride” needs afternoon shade. — G.H., Email

A. There are several types of sun-loving hydrangeas, including the Pee Gee hydrangeas, or hydrangea paniculata. These are very hardy hydrangeas that mostly bloom white or cream, then turn rose or lime green depending on the variety. Some can be trained into tree form or even purchased as “standards,” which is a nursery term for a shrub trained to grow like a tree. Look for Limelight, Little Lime, Quickfire, Pinky Winky, Bobo, and the showy Zinfin Doll with huge pointed blooms that turn rosy pink.

The hydrangea with the largest flowers is called “Incrediball” and the blooms really can be the size of a basketball. I am trying a new variety called “White Wedding” and the creamy flowers have not burned at all during our hot weather this summer.

One more hydrangea class that can take the heat are the oak leaf hydrangeas, or hydrangea quercifolia. They have huge leaves that turn a rusty red in the fall so this large-growing shrub will be the star of a fall foliage garden.

Local nurseries will carry many more varieties and this is a good time of year to shop for hydrangeas in bloom. That white hydrangea called “Blushing Bride” is not a Pee Gee variety and does indeed need afternoon shade to keep the blooms from burning — but it is oh so beautiful if planted in a spot that gets just morning sun.

Q. I have heard that cutting your hydrangeas at the wrong time of year will cause them to not flower the following summer. I have a blue hydrangea and want to cut some of the flowers to dry. Will this stop it from flowering again? — P.P., Tacoma

A. Go ahead and get snippy now. Fall is not the time to cut back hydrangea shrubs but cutting the stems with flowers is OK because most of the blue-blooming, big leaf or Hydrangea macrophylla varieties flower on 2-year-old wood, so the stems that are blooming now won’t flower next summer anyway.

An exception to this are the “Endless Summer” hydrangeas that flower on new and old wood. The sun-loving hydrangeas mentioned in the previous question (Pee Gee Hydrangeas) also can have their flowers harvested now, but do not do any serious pruning of the Pee Gee hydrangeas until early spring.

Tip: Not all hydrangeas need pruning. Most bloom best if you give them lots of room and leave them alone.

Q. Every year I buy a potted mum from Costco. Then it wilts and dies. Why? — J., Bonney Lake

A. My guess is lack of water. Potted mums are packed with roots as several small plants may be grouped into one pot. They may need water every day to keep them from drying out.

However, do not let the pot sit in drainage water. Fill a watering can with water and set it near the potted mum. This is your visual reminder to check the soil and water when dry. Potted mums may need watering twice a day during hot weather.

Zoom talk on changing gardens and changing gardeners

I will be doing a Zoom talk at 6:30 p.m. Sept 15 on ”The Changing Garden and the Changing Gardener: Tips for climate change, senior gardeners and refreshing a boring landscape.” Participants need to sign up for this talk ahead of time and pay a $25 fee to join the seminar. The event is a benefit for Master Gardeners Foundation of Thurston County, and will include fun prizes including a tour of my garden. To register and pay, visit mgftc.org

Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.