September is time to both plant and harvest in the Northwest

The fourth week of September means the planting season for adding new trees and shrubs is still in full sway.

Another thing swaying are the many ornamental grasses that take pride of place in the late summer and early fall landscape design. If you are looking for a perennial plant that attracts wildlife and uses less water, then consider waves of amber grains and wispy blades of grasses as the answer to a more sustainable landscape.

But do your research. Some grasses are difficult to cut back in the spring, some reseed all over and some just look like weeds if not grouped together and cared for.

Things to do this week include buying and planting spring flowering bulbs, fertilizing the lawn with a fall and winter plant food if you have not yet done this, and keeping up with the harvest of edibles.

Don’t allow fallen fruit to sit on the ground where it will rot and attract disease and other pests. Keep two buckets nearby. One to hold fruit that looks good enough to eat, bake or donate to the food bank. The second bucket is for rotting fruit that gets buried in the compost pile.

A few things not to do this week

Do not prune back tender plants such as salvia and hardy fuchsias. Do not give roses a hard pruning now.

Fall is also not the time to spray for cranefly as the large mosquito looking creatures clinging to your windows and screens are best left to the birds to control. Cranefly, tent caterpillars and even aphid have cycles of outbreaks in certain years.

Fall is also not a good time to use a weed-and-feed product on your lawn. Cool weather makes herbicides less effective.

Hydrangea happiness

So many new and improved hydrangea varieties are on the market, which means I am not the only one collecting these late summer and fall flowering shrubs. If you follow me on Facebook, Instagram or YouTube, you may have seen my “Hydrangea Room,” an enclosure with walls of blooming hydrangeas and a wood chip floor.

(Yes, my hydrangea room is where I found a real blue-eyed baby inside a basket earlier this summer! Don’t worry. She was a grandchild, placed among the hydrangeas as a garden accent — a surprise that made a great video.)

Fall is a great time to transplant or move your old hydrangeas or to add the new and improved hydrangea varieties to your landscape. Hydrangeas are easy to move with rather shallow roots and can be pruned back hard when you transplant to make the shrub less awkward to move.

Here are some tips for adding hydrangeas to any garden:

Hydrangeas for sunny spots: The Smooth Hydrangea, Panicle Hydrangea and Oakleaf Hydrangea.

Smooth Hydrangeas (Hydrangea arborescens) are very cold hardy, take full sun in our climate and include the traffic-stopping, huge balls of blooms from varieties like Incrediball, and the tough Invincibelle series. Annabelle is the smooth hydrangea that started all the fuss for these outstanding shrubs, but new breeds means you have a choice of pink, white and dwarf smooth hydrangeas that will not wilt on hot afternoons.

Hydrangeas for small gardens: Invincibelle Wee White, Pia, Pistachio, Invincebelle Mini Mauvette and those that bloom on new wood such as Endless Summer, Blushing Bride and Penny Mac.

The best way to grow the old-fashioned hydrangeas (Hydrangea macrophylla) is to plant them as huge hedges — which is how I gained a hidden hydrangea room. Smaller gardens can still host hydrangeas if you are picky about the variety. Trying to keep a hydrangea small by pruning is just not practical if that variety flowers on two-year-old wood. This includes most of the old-fashioned mop head hydrangeas with big round blooms.

But the newer hydrangea varieties that flower on new and old wood can be pruned a bit in early spring and the new growth will bear blooms. The Endless Summer hydrangea is the best known, but the white to pink Blushing Bride is a hydrangea that not only flowers on new wood but also does well in a large container.

The best way to determine the size of a hydrangea is to read the tag at the nursery – then add a few more feet. In our mild winter climate, most shrubs grow larger than what it says on the plant tag.

If you want a compact hydrangea for a sunny site, the Little Quick Fire, Pinky Winky and Zinfin Doll are all panicle hydrangeas (Hydrangea paniculata) with pointed blooms that start cream or green and turn pink. These hydrangeas do best when pruned in early spring by one third. Getting snippy in March can keep the dwarf Paniculata hydrangeas at under 4 feet tall.

Hydrangeas to grow as small trees: Grandiflora, Pee Gee.

This is the hydrangea tree that has such a high price tag at the nursery. But you can form your own tree just by pruning a Pee Gee hydrangea into a form with a single trunk. Stake the trunk the first year or two and let the top branches grow outward. A Pee Gee hydrangea trained as a standard or tree form is a lovely hydrangea to grow at the corner of the house as it offers months of color.

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

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