Ask the gardening expert

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I planted a smoke tree in the backyard (full sun). The blossoms and leaves were a burgundy/purple color but now it is more green. Does it change colors toward fall? How do I get the color back?

Purple smoke tree should retain its purple color throughout the year as long as it gets adequate sunshine. Sometimes the foliage starts out green and then changes to purple as the weather cools. This is probably what is happening to your plant. It should turn purple in the fall. I'm sure the tree will be the desired color next spring when the new leaves come on if it's in enough sunlight.

I have three 5-year-old hydrangeas on the north side with partial shade. This year the blooms are very light pink. How can I deepen or change the color?

You can change the color of hydrangea blooms with a simple soil treatment. Pink and red hydrangeas often turn blue or purple in acid soils, and plants can be made red by liming the soil or applying superphosphate.

For blue flowers, treat the soil with 2 Tablespoons of aluminum sulphate per plant, making 4 to 6 applications at 2 week intervals, starting in the early spring before the plants bloom. Sulfur will acidify the soil. The desired pH range would be between 5.5 and 6.

For pink flowers, add lime to the soil, to raise the pH above 7.8. Test your soil to measure the pH range. I'm not a big fan of attempting the color change, I feel the colors are not as clear -- they have a "muddy" cast that I am not fond of. I like to keep a pink blooming plant pink by growing it in a good sized container where you can control the additives and enjoy the colors of the original.

We had some fairly good success growing vegetables in containers this last summer/fall. Now I find myself looking ahead to the next garden season. I'm wondering what you might recommend I do to have a repeat of this season? Should I rotate vegetables varieties? I'm sure I will need to thoroughly clean the containers before I re-fill with soil. I'm hoping to learn about organic pest control in my containers as well. Is there a resource you could recommend for this part of the country?

So glad you asked. Yes, there is a rather new spiral-bound book based on the work of our county agent Charles A. Brun Ph.D, Horticulture Advisor, Washington State University Extension Service in collaboration with Clark County Environmental Services, titled, "Organic Pest Management for Home Fruit and Vegetable Gardening." There are free copies available at the Extension Office located at the Heritage Farm in Hazel Dell.

The publication is well arranged to aid in identification of a problem, and what one might do about it. I feel it is a helpful and well thought out addition to any serious organic gardener's library. Most vegetables will adapt to growing in containers. Tomatoes have deep roots so I grew mine in half whiskey barrels, and they did great. The rest can grow in 2 to 3 gallon containers. Use potting soil for your veggies and rotate the kinds of veggies you plant in the containers -- just in case the soil is harboring any disease pathogens. Make sure your containers have adequate drainage holes, set them in full sunshine, and water as often as necessary to keep the soil moist but not soggy wet.


Celeste Lindsay is a WSU-certified master gardener. Send questions to mslindsay8@gmail.com