I am having a hard time accepting that September is upon us already. The school year is beginning once again and fall will soon be in the air. In all honesty, autumn is my favorite season in the garden (without question), but having said that, I am in no hurry to say goodbye to the summer sunshine. Mother Nature will bless us with seemingly unending rain soon enough, and after this especially long and dry summer season, we all should welcome it with open arms.
I thought it might be fun this week to discuss some late summer projects in the garden, including some things that I consistently see gardeners doing that should not be done right now. Perhaps it is time for you to plant cool season veggies to then harvest in fall? Maybe some spring bulbs that are arriving this month will catch your fancy? These are just a couple of examples, but keep in mind that there are always pertinent projects to plan for and accomplish all year long. Optimizing the timing of these tasks can lead to even more consistent success in your landscape.
Pruning: This is a tough one for OCD people like me, but with a few exceptions, you really want to avoid heavy pruning in late summer and fall. If we consider deciduous plants first, many old-wood bloomers have already set their flower buds for 2026; Magnolias, Lilacs, Flowering Cherries, Crabapples, Forsythia, Quince and countless other examples come to mind. Cutting plants like these back now does not allow enough time for them to regrow and set flower buds for the coming season. Will you kill your plant? Probably not, but you will definitely be minimizing your plant’s flower power. Removing dead or diseased limbs can be done anytime, but if shaping and/or directional pruning are required, wait until after frost in later fall. Thin these plants over winter and then remember to “prune after bloom” for best results. Perhaps even more important are broadleaved evergreens; plants like Boxwood, Japanese Holly, Laurel, Osmanthus, Nandina and many others should be left alone at this point. I always tell gardeners to mark July on the calendar as the tidying of hedges and shrubs such as these needs to be done no later than that. Pruning right now does not allow enough time before frost for each specimen to regrow and harden off. You will end up with burnt tips and a lot of brown foliage over the winter, which will require another pruning coming out of winter to correct the problem. To take this a step further, consider old-wood blooming PNW garden gems like Azaleas, Rhododendrons, Camellias and Pieris as examples of plants that have flower buds set NOW for 2026 – cutting them back means no bloom for you next spring. So long story short, put the pruning weapons on ice and bring them back out later in winter and spring to start the pruning cycle for 2026.
Deadheading: You can always remove spent flowers anytime, so have at it! Annual plants of all kinds should be done, as well as many of the perennials we use locally. Perennials in particular will keep blooming a bit, if you tell them not to go to seed by removing spent flowers. This may also help your Hydrangeas as removing their old blooms will help them send more buds out as well. Lavender is one plant that is vastly abused in our area – remember to shear after each bloom for a more compact, tidy and attractive plant. If you do not, you will have a woodier specimen with a just a frosting of foliage. Get them coming out of winter again as well.
Weeds: As we near the end of summer sunshine, get your weeds sprayed. The warmer and drier it is, the more effective your spray will be, particularly if you utilize organic products like I do. The wetter days and cooler temps of fall make it tougher to apply, and honestly less effective for the 100% killing of root systems. This can include the lawn, driveway, gravel areas and anywhere else you have undesirable vegetation. One person’s trash is another one’s treasure, as I say with plants, so you need to decipher what is a “weed” to you and make your decisions accordingly.
Fertilizing: This is another tough topic for gardeners to grasp, including me on occasion. Using organic foods, first and foremost, is always the way to go. With the vast majority of perennials, shrubs and trees, I try to get folks to stick with one feeding coming out of winter and another (if needed) in early summer, around June. This late in the season food should not be required; you do not want to encourage a bunch of new growth at this point, as again there is not enough time for new growth to harden off before first frost. Planting new specimens into the landscape is a huge exception – absolutely make sure to use a quality organic transplant food like Sure Start from E.B. Stone Organics as this will gently encourage root establishment. Applying a fall dose of lawn food is another exception since feeding your turf in fall is the single most important time to do so. Roses can also be fed one more time in early September and then they are good until spring when you should feed them again in March. Gardeners can also keep feeding their annuals in container gardens, baskets and in-ground plantings as well to keep them fresh and lively. The point is to focus your efforts on the few things listed above and avoid feeding the entire landscape this late in the gardening season. Put that bag of organic goodness in the garage and bring it out next March to kick off the 2026 gardening season the proper way.
Watering: After this exceedingly long and dry summer, our soils are very dry, perhaps even hydrophobic in some instances. Fall rains will help immensely, but plants will continue to need adequate irrigation. I bring this up now before the important planting season known as fall. Autumn is the best time of year to plant just about anything, but soil needs to be moist to receive your new garden treasures. Water deeply in dry areas, even filling holes with water to saturate them and then amend with compost. Once planted, water them again and mulch with even more compost. Since I mentioned fall is for planting here, keep those trouble areas like slopes top of mind. Autumn is ideal (with lots of rain coming) to plant these areas, preventing erosion and allowing things to get established over the winter. Plant enthusiasts of all kinds would be truly shocked if they could see how much root development occurs over the “dormant” season!
As fall beckons, a visit to the local garden center to discuss these tips (along with others) will help. Speak with a Certified Professional Horticulturist about your needs and allow them to steer you towards gardening success. It is a great time to get ahead on a few things, while waiting on some others may be a more prudent decision. Walk about your landscape and formulate a gardening battle plan, then take advantage of fall clearance sales at your local garden center. After that all that is left is to try to find some late summer shade, sip on a favorite cold beverage or two of your choosing and enjoy the rest of summer. Anything less would be uncivilized.
Remember, leaves up, roots down…
