September marks the beginning of the second planting season.
It's true – fall is for planting! The soil’s still warm, and that’ll provide for faster root growth and give plants a bit of a head start. By next summer, they’ll have larger, more established root systems that allow for improved drought tolerance and better growth throughout the first year.
Shorter autumnal days and mild temperatures mean lower stress on new plants, and the inevitable rains help keep those new plants watered-in—which means less work for you (and maybe a few extra days leftover to enjoy the hammock).
Fall is also a great time to shop for hardy plants! We’re always stocking up on conifers, winter-blooming shrubs and Pacific Northwest native plants this time of year. Fall favorites—like pansies, ornamental cabbages and kales, and overwintering vegetables and herbs—are all available here at Portland Nursery.
Some plants are borderline hardy for your area and may be challenged by the extreme cold—and because of that, they should be planted in the spring, and that will allow their roots to develop before freezing temperatures arrive.
In Portland it’s generally safe to plant anything that’s hardy to Zone 7 and below in autumn, but popular Zone 8 plants—like New Zealand flax (Phormium), star jasmine (Trachelospermum jasminoides) or hardy Gardenias—should wait until spring.
If you choose to install Zone 8 hardy plants in fall, you’ll need to develop a plan for protecting them during harsh winter weather events.
Spring flowers are such a delight after a cold, dark winter; snowdrops can poke up even in the midst of a late winter snowfall. Combine bright, cheerful blooms such as Crocus, Eranthus hyemalis (Winter Aconite), and Galanthus nivalis (Snowdrops) with Hellebores and Andromeda to herald the first signs of spring.
Take advantage of fall planting, while the days are still warm and the soil is softened by early autumn rain showers. Beginning in mid-September, we carry up to 400 different varieties of bulbs.
Some of your summer annuals may be a bit tired looking or overgrown. In some cases a trim and a bit of water-soluble fertilizer will get you a few more weeks of bloom. Others should probably be discarded in favor of some new fall color. This means those annuals and short-lived perennials that look great now through autumn and often times into winter. Pansies, kale, dusty miller, mums, asters, and black-eyed-susans are all examples of this. There are plenty more flowers to enjoy; the growing season isn’t over yet!
As for perennials, the late-season flowers are in full swing and full stock on our shelves; asters, many daisy style plants, yarrow, and salvias are blooming nicely. The beginning to middle of autumn is one of the best times for planting assuming temperatures have cooled since summer. The majority of cold hardy perennials thrive with fall planting since their root systems can grow all winter and emerge in the spring ready to grow.
If you have poorly drained soil you may want to wait until spring to plant perennials that require good drainage such as penstemon and lavender. Once the weather has cooled down, it is also a good time for dividing established perennials, though October is the more common month for that.
Bulbs! It is finally that time again! Tulips, daffodils, hyacinths, alliums, crocus and many others are available for purchase starting in September. While refreshing those flowers beds and containers with some pansies or other fall color, add some spring flowering bulbs in there as an investment in next year’s show.
Some bulbs can also be grown in pots, often indoors, during the late autumn and winter. This is generally called forcing. The most common bulbs for this are paperwhites (Narcissus ‘Zeva’) and amaryllis. While they can be started as early as September, most people prefer to wait until October for amaryllis or November for paperwhites to try to match the bloom period to the holiday season. Other people start a few more paperwhites every week to extend the season of enjoyment.
September is a good time for starting a fresh round of cool-season and overwintering crops. This includes lettuce, spinach, and other greens, as well as some cole crops such as broccoli and cauliflower. Short season root crops such as radishes can be grown now to harvest before winter, and overwintering roots such as garlic and onions can be planted.
Just as importantly, its harvest time for those warm season crops! Here are some tips on harvesting different groups of vegetables:
This marks the beginning of the autumn planting season. While it is possible to plant trees and shrubs in the heat of summer, it is often easier on the plant if you wait until the temperatures cool somewhat in September or October. Also, if you have clay soil it is often easier to dig in after the first significant shower of the autumn.
We always stock up on conifers this time of year. Many of these are quite unusual and this is the only time of year that we get some of them. Be sure to stop by frequently to see what we have in new arrivals.
Caterpillar damage is at its height in autumn. While many of the less damaging leaf eaters can be ignored because the leaves are going to fall off soon, tent caterpillars can do extensive damage if ignored. A large population can kill major branches of mature trees. Common targets include birch, ash, and maple. Insecticidal sprays can keep the population low.
Most trees and shrubs don’t want to be fertilized this time of year. The only exception might be a little organic, slow-release food for newly planted evergreens, or those plants that have not been fed in a long time.
September is the month for renovating that summer-weary lawn. First, dethatch if you have not done so in the last year. This is done by thoroughly raking out the dead matter underneath the growing grass blades. Then, assess how full your lawn really is and make appropriate plans to reseed, overseed (applying seed to an existing but patchy lawn), or install sod.
If your lawn is really patchy or almost nonexistent reseeding is best. Turn the soil and mix in some compost. Level it out and add seed, fertilizer, and lime. Cover the seed with a very thin layer of peat moss or fine compost (no big woody chunks). Keep moist and keep the weeds away; you should have a great lawn before winter.
If you are over-seeding, then skip the bit about turning the soil, but a thin layer of compost on top is beneficial before laying the seed, fertilizer, and lime. If installing sod, turn and amend the soil beforehand, and fertilize and lime after installation. Link to our pdf, Installing a Seed Lawn, to see these steps in detail.
Visit individual month pages for gardening ideas. Pages are regularly updated with projects for that month.