The last week of August means the start of autumn maintenance and fall propagation in the garden.
This is the time to cut back, take cuttings, dig and divide early blooming perennials and start filling up the compost bin. Continue to harvest herbs, veggies and cut flowers from the garden and keep all of your beds weeded so that the summer weeds don’t get a chance to flower and go to seed.
Watering is the most important task this week especially if you want a landscape that will continue to look great all season. Remember to water slowly and deeply to train the roots of trees, shrubs and perennials to grow deep in search of moisture rather than stay at the surface of the soil. Drip lines, soaker hoses and improving your soil with compost and organic matter are all ways to cut back on the water bill.
Q. Is it safe to use “gray water” to water my container gardens? By this, I mean the leftover water from cooking or washing? I live in a town with high water bills and my summer water bill is a shocker. – R.T., Email
A. Reusing water can be a bit of a dirty issue.
Never recycle water that has soap suds unless you are sure the soap is mild with no phosphates. This means if you hand-wash dishes with Ivory soap and then occasionally use the water in the dish pan to water your pots you’ll be fine.
Don’t recycle water from washing clothes. A practical way to cut back on wasted water is to recycle the water from cooking vegetables. Just don’t salt the water and let it cool before using it to water houseplants, hanging baskets and container gardens. As a bonus the nutrients that leach from the boiled veggies will help to fertilize the potted plants. If you hand boil eggs, this cooking water is an excellent source of calcium for tomatoes and blooming houseplants. Again, remember not to add salt to the cooking water if you recycle it onto your plants.
My raspberries have borne fruit and now the branches are turning yellow. When do I cut these back? – C.C., Olympia
This is a good time to cut back the canes of June-bearing raspberries that have already given you a harvest. When you see that the foliage has turned yellow and brown, get snippy all the way to ground level. Cutting back the canes now will allow the new growth from beneath to take over. Don’t prune back the new fall-bearing raspberries or everbearing raspberries as you can still enjoy a late harvest this fall. In general for all plants this time of year, if the leaves are green, let them be, if it’s brown, cut it down.
I have bearded iris plants that have grown ugly with age and now have less blooms. I suspect I need to divide them. I have read you should do this in the fall. My question is what month is considered the best for dividing iris? – M.K., Email
Dig in now as late August and the entire month of September are the perfect time to divide early-blooming perennials like iris, poppies, pulmonarias, and hosta. Don’t divide hellebores and wait until the weather cools in late September or October if you must divide or move peonies. The tip for happy bearded iris is to make sure you don’t plant the thick and knobby roots too deep. You can cut back the tall and spiky foliage to just six inches tall when you replant and toss out the older, center section of the iris corms. Iris need full sun and well-drained soil – and don’t forget the slug bait.Marianne Binetti is the author of “Easy Answers for Great Gardens” and eight other gardening books. She has a degree in horticulture from Washington State University and will answer questions at her website binettigarden.com.