Now’s the time to fertilize and water to keep your roses and other flowers blooming
The first half of July is your last chance to fertilize roses to keep them blooming all summer. In our climate, feeding roses later in the summer can encourage late growth that will be damaged by a first frost.
Watering roses and perennials is important this week as plants decide if they want to start a second generation of blooms. Water slowly so that the moisture sinks down 8 to 12 inches into the soil. This will cause the roots to follow the moisture downward, and deep roots are the answer to survival during the hot, dry month of August.
Q. I am new to the area. How late can I add roses to the garden? Also where can I see roses in bloom to decide what type of rose I want to add to my landscape? — T.H., Tacoma
A. You have a rosy future here in Western Washington as potted roses growing at a nursery can be added to the landscape all summer and into the fall. The secret is to soak the soil the night before the transplanting — both your potted rose and the planting hole. Try not to disturb the roots as you slip the potted rose into the planting hole after amending the soil. Settle in the new plant with more gentle soaking.
As to where to see a diverse rose garden? Visit the Point Defiance Park rose garden in Tacoma any time in the summer to see not just hybrid tea roses but climbing and shrub roses as well. Most of the roses at this park are nicely labeled so you can find them for sale at local nurseries.
Q. I have lilies that bloomed well. Should I cut off the flowers and cut down the stems once the blooms have faded? — G.H., Olympia
A. Yes and no. Yes to cutting off the faded flower on all lily plants, but no to cutting back the tall stem with the foliage. Lilies need the green leaves on that stem to make food for next year’s lily blooms. This is why experienced gardeners grow lilies behind lower growing plants or amidst other plants where the bloomless stems will not stick out like flag poles without their banners.
Q. My phlox always gets mildew. I heard you speak on a webinar about a white phlox that would not get mildew or rust in Western Washington. I forgot where I wrote the name down. Could you share the name of the disease resistant phlox again? — W., Email
A. Look for the tall, white and handsome phlox called David to grow in our climate, and remember to avoid getting the foliage wet to discourage mildew and other fungal infections. Over feeding plants can also make them more prone to disease — too much plant food encourages soft, weak growth. One application of slow release or organic fertilizer to garden phlox in early summer is enough. Improve your soil with organic matter and you will help to ensure healthy plants that are better able to resist mildew and other fungus among us.
Meet Marianne
11 a.m. Friday, July 18: Join Marianne at the Bellevue Botanical Gardens for a free walk and talk on “Perennial Power for Summer Color.” The gardens are in Wilburton Hill Park at 12001 Main St., Bellevue.
10 a.m. Saturday, July 19: Join Marianne at the Shark Garden in Burien for a free seminar called “Winning the War on Weeds.” Also known as New Start Community Garden, the Shark Garden is at 614 SW 120th St, Seattle.
Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.
This story was originally published July 12, 2025 at 5:00 AM with the headline "Now’s the time to fertilize and water to keep your roses and other flowers blooming."