Have you noticed white powdery appearance on leaves and other green parts of your plants? It’s likely powdery mildew fungus, a common disease that can be found on squashes, roses, dahlias, cucumbers, pumpkins, azaleas, dogwoods and many more plants. The fungus often causes leaves to wilt, turn yellow, drop from the plant or curl up. The fungus thrives in moderate temperatures and high humidity, and tends to favor plants in shady, overcrowded areas.

On roses, you’ll find the powdery white growth on leaves, stems, buds or flowers. It typically appears on new growth during warm, dry days followed by cool, damp nights. The leaves may curl up, or look badly distorted. You may see tiny black spots amid the white talcum-powder dusting.

What can you do to prevent powdery mildew? Try to plant varieties that are resistant to the disease (for dogwoods, for example, C. kousa is a good choice). Plant roses, for example, in sunny spots, not shady areas that tend to take longer to dry out. Promote good airflow with selective pruning and proper spacing so plants don’t crowd and shade each other out, which encourages spore germination. Remove diseased parts of the plant and destroy all dead leaves (do not compost these clippings) since the fungi can survive the winter. Avoid overhead watering and getting the leaves wet especially late in the day when there’s no time for it to dry.

Cornell University has this good fact sheet on the disease. Researchers have discovered that baking soda combined with a horticultural oil can help fight powdery mildew on roses and other plants. Spray your plant about once a week with a solution of baking soda (1.5 tablespoon/gallon) and horticultural oil (3 tablespoons/gallon).

The June pest of the month is the earwig. This is their peak time of the year. They’re ugly little suckers, and distinctive in their look: dark brown long body with light brown legs and forceps at the rear. (Those pincers are harmless to humans). They’re nocturnal pests, so they come out at night. During the day, they tend to hide in moist, cool shady spots, including under leaves, garden pots, wood or compost piles, mulch. Some feed on aphids, insect eggs and mites, which is beneficial, but they also tend to snack on seedling plants, fruit crops such as strawberries, and flowers such as dahlias, zinnias and marigolds. You’ll find tiny irregular holes in the leaves, or you’ll notice that the leaves have been chewed around the edges.

How do I get rid of them? Trap them. Set out several homemade traps in your yard. One suggestions is to fill an empty tuna can (or other shallow can) with about 1/2 inch of vegetable oil. When the earwigs fall into the oil, empty the cans, refill with oil and set it out again. Another option is to use a moistened rolled-up newspaper or short piece of rubber hose. Put them out before dark and when you get catch some earwigs, shake them out into a pail of soapy water.

Try to eliminate areas where earwigs like to hang out. That means making sure you don’t have piles of yard debris, leaves, wood or other hiding places, especially near your vegetable beds.

Growing herbs indoors or outdoors is one of the most economical benefits of having a garden. Some herbs are no-brainers, like rosemary, Italian parsley, oregano and mint, because they require very little attention and buying sprigs of those herbs can be expensive. Other herbs such as basil and cilantro are a bit more finicky, but not impossible.

oregano

Most herbs require some amount of pinching/pruning to keep them full and happy. Make it a regular part of your harvest and it won’t seem like work at all. I regularly cut back rosemary, mint, parsley and basil as I need it, but sometimes even when I don’t. I want to keep the plants full and bushy.

Rosemary, thyme, sage, oregano and savory can tolerate dry conditions. They’re also great low-maintenance plants for your landscape because they require little water. Basil, lemon balm, dill need a bit more moisture. Mint likes wet soil, and should be planted in containers to prevent them from taking over your garden.

Here are some other tips to growing herbs:

Basil: Likes sun! Pinch out stems to create side shoots, and encourage full, bushy growth. Keep the plants well picked. When flowering starts, pinch off each flowering shoot and the leaf pair directly below. This Oregonian article has a good illustration of where to cut.

Cilantro: Perfect herb for Northwest climates because it doesn’t like hot weather. Cilantro prefers cool but sunny conditions. Too hot and it bolts (flowers). The flowers produce coriander seeds, which are also used in cooking. I seeded some a few weeks after I planted my peas earlier this spring, and have periodically re-seeded it with good success. Great for that guacamole!

Parsley: This herb is easy to grow from seed, but are readily available as starts.

rosemary

Regularly prune parsley and don’t allow them to go to seed. Trim large stems every so often.

Rosemary: A must have in the northwest.  Regularly prune rosemary, cutting off about a quarter or so, to prevent the plant from growing woody. Rosemary loves full sun, and can tolerate dry conditions nicely. In my opinion, you can’t prune rosemary too hard.

spittle bug foam on lavender

If you’ve noticed frothy white foam on your plants around this time of year, it’s a sure sign of spittle bugs. Spittle bug nymphs hide (and feed) under the foam for protection.

We’ve spotted some on lavender and rosemary in our garden in recent weeks. Don’t worry. They’re not pretty to look at and the bugs do suck some plant sap, but they’re not particularly harmful to your plants.

How do you get rid of it? You can hose the foam (and nymphs) off with a strong spray from your garden hose, or hand pick the nymphs and destroy them. Or you can leave them alone, since they tend to disappear in a few weeks. You tend to see spittlebugs in the Northwest around May and June.

One of the most common questions we get from clients is how to get rid of weeds without using pesticides. If only there was a magic wand that allows you to sweep it over weeds and make them disappear. Too bad there’s not. But there are many ways to keep up with weeding so it doesn’t take the joy out of gardening.

1. Hand pull weeds when they’re young and don’t allow them to go to seed. Pull them in the winter and spring time and keep at them throughout the summer.

2. Where possible, mulch your landscape beds to keep weeds down. A thick layer of bark mulch, applied once a year, will work miracles.

3. Build good soil underneath lawns to help crowd out weeds. If you spend time properly establishing your lawn, the grass will grow thickly and help prevent seeds from germinating. Weeds, however, are inevitable, but you can prevent many of them in your lawn by properly watering your lawn, mowing it frequently (and high) and keeping it fertilized. Avoid weed and feed products that simply broadcast herbicides over the entire lawn. It’s overkill. Rather than directly targeting a specific weed, it “sprays” the entire lawn with the stuff. All of this washes into our drains and into the Puget Sound. If you hand-pull large weeds, be sure to fill in the gaps with a mixture of compost and grass seed. This prevents weeds from filling in the space.

4. Use cover crops (crimson clover is one of our favorites) to fill empty spaces during the winter where you’re not growing anything. Cover crops, also called green manure, build healthy soil.

5. Fertilize and water plants directly and avoid areas where you’re not growing plants.

Since moving into my West Seattle house five years ago, I’ve been on a mission to reduce the amount of lawn on the property. My goal was to get rid of about two-thirds of the lawn, leaving only a small area in the front of the house and the side yard for the dog. A quick way to get rid of lawn is to rent a sod-cutter, cut up the sod and haul it away. But this can get expensive, especially if you have a large-sized lawn. Sheet mulching is a cheaper alternative though it requires more time and patience. It’s great for controlling weeds, improving soil and getting rid of grass. The idea with sheet mulching is to kill the lawn (and any weeds) by putting down an organic weed barrier that breaks down over time while keeping sunlight out. After about six to nine months, you’ll have a rich soil that you can plant in.

Here’s a step-by-step guide to sheet mulching

Step 1: Mow the lawn as short as possible.

Step 2: It helps to add compost or chicken manure to the lawn to help jump start the decomposition process before you lay down your weed barrier. The high nitrogen in the compost or manure will help build good soil.

Step 3: Soak the area with water.

Step 4: Put down your organic “sheet mulch,” or a weed barrier that kills the lawn and weeds and prevent weed seeds from germinating. You can use several layers of newspapers, cardboard boxes or burlap bags. Make sure to lay down several layers of whatever material you use and overlap them so there’s no gaps where weeds or grass can push through.

Step 5: Add a thick layer of compost, grass clippings or leaves over the weed barrier, about three inches thick. Many people skip this process altogether, but I personally think it’s worth the time and trouble. If you do it right the first time, you’ll have rich soil that you won’t need to fuss with later on.

Step 6: Add a layer of top dressing such as leaves, wood chips, bark or sawdust, about three inches deep.

Step 7: Wait for time and earthworms to do the work. Over time, this top layer will break down with the other layers beneath it, and you’ll have rich, loamy soil. If you’re anxious to plant, you can cut a hole in the weed barrier (newspaper or cardboard).

We have sheet mulched large areas of our planting strip (the no-man’s land between the sidewalk and street) and front lawn with great success. It took about six months to a year before things really broke down, but we were slowly able to add plants to our landscape beds by digging through the layers. Our entire side yard, about 600 square feet, was sheet mulched a couple years ago, and is now the site of a rich, productive vegetable garden.

The past week has brought gorgeous sunny weather — even surprisingly high temperatures — to the Puget Sound area. That’s been great for our vitamin D-deprived bodies, but our plants may be feeling the heat. This week has been the perfect time to tap into your 50-gallon rain barrel (hopefully you have at least one installed at your house) to use up the water that you’ve stored from the spring. (For where to buy in Seattle, go to the Seattle Public Utilities Web site; for King County information, check out this site).

Rain barrels allow you to catch rainwater off your roof during rainy days, and to store it to use during dry periods. Seattle relies on mountain snowmelt for its water supply, so water is precious during summer months (especially if we’ve had less snow than usual the previous winter). Water rates also jump in the summer months, so rain barrels can help you save money and conserve water.

We have two rain barrels that we bought from the city of Seattle and have set up in the backyard to water our non-edible plants. Should you use the rainwater from your roof on plants that you eat? We err on the safe side and use the water exclusively for our non-edible plants. We have plenty of other trees and shrubs to water, and our vegetables are already on an efficient drip-irrigation system.

Over the years, I’ve found that the easiest way to water plants, especially trees, is to buy a few cheap 5-gallon buckets, poke a hole near the bottom of each bucket and set them under the rain barrel to fill one at a time.  Once a bucket is full of water, I’ll set the bucket out near the base of a tree that needs water while another bucket is being filled under the rain barrel. Trees, shrubs and other plants like the slow, deep irrigation that trickels out from the small hole in the bucket. The slow-drip allows the water to seep into the soil more deeply rather than just running off the ground surface or evaporating.

It’s tempting for many of us to pull out the heavy-duty bottle of pesticide when we find insects, diseases or weeds in our landscape. We want the problem to go away, and go away fast, whether it’s powdery mildew on our squash or aphids on our roses. But before you bust out the sprays, consider that pesticides are toxic to pets, birds, bees, and fish, and end up in our waters. (Check out the Washington Toxics Coalition site to read more about it).

You can adopt a more gradual approach to dealing with pests and plant diseases by identifying the problem and then trying less-toxic methods of getting rid of it. You’ll often hear people call this process IPM, or Integrated Pest Management, but really it’s about using common sense to tackle the problem.

First, identify the problem. It’s possible that it’s not a nasty disease attacking your plant, but symptoms that you’re watering too little or too much. Or you may find out that the bugs in your garden are actually good, beneficial insects such as lady bugs and lacewings that eat bad bugs.

Once you’ve identified what’s wrong, find the least toxic way to get rid of it. Aphids, for example, can be controlled by hosing the plant down with water. Other pests and weeds can be removed simply by hand-plucking them from the plant.

Prevention is also a good way of keeping these problems at bay. Pick plants that are disease resistant, thrive in your climate, and grow well in the site you chose for it. Reduce plant stress by watering, pruning and fertilizing properly. Use barriers like mulch to suppress weeds or floating row covers to keep bugs away. Check out these fact sheets on less toxic ways to deal with snails & slugs, spider mites, roses, and more.

If you live in the Seattle area, it’s inevitable that you’ll run into a patch of heavy clay soil somewhere on your property. The parking strip on the south side of our West Seattle house is mostly clay, and the sole plant that we have out there, a dogwood, doesn’t thrive as well as other plants and trees on our property.

So what do you do if you have clay soil? Whatever you do, don’t add sand to your clay thinking that it will improve the soil. It’s a big no-no and one of the biggest myths.  Sand + clay = cement.

Adding organic matter — such as grass clippings, shredded leaves, composted manure and compost — is one of the best things you can do to improve clay soil conditions. Remaking a landscaping bed is a good time to do it. Dig it into the soil down about 6 to 8 inches deep. Tilling the soil and adding organic matter makes soil more permeable, allowing water to drain. The organic amendments will decompose over time, and help improve the soil structure.

If you’ve got clay soil under your lawn, try aerating the lawn, which pulls core plugs of soil about three inches long and then plug the holes back in with compost.

Some trees and shrubs, however, will do well in clay soils, such as gingko, witch hazel, burning bush, honeysuckle, potentilla, spirea and lilac. When you plant in heavy clay soils, try to plant the trees and shrubs a few inches above the grade of the surrounding soil.

To read more about improving clay soils, click here.

Want to know what’s killing your dogwood or how to properly prune your roses? Looking for a less toxic way to get rid of slugs, aphids and other pests? Got a tree or shrub that you need help identifying?

Starting this month and through early September, you’ll find gardening experts who can help answer your questions at dozen of Master Gardener clinics throughout King County. Master Gardeners are volunteers who go through a rigorous training program by Washington State University. They provide research-based information on home gardening and pest control.

In West Seattle this summer, Andy will periodically be staffing the Master Gardener booth at the West Seattle Farmers Market, and I can be found at McLendon Hardware in White Center. Here are the hours & location:

West Seattle Farmers Market, 44th Avenue SW and Alaska Street, April 27-September 14, Sundays, 10 a-.m.-2 p.m. (No clinic May 4).

McLendon Hardware, 10210 16th Avenue SW, April 5-September 13, Saturdays, 10 a.m.-2 p.m.

But don’t limit yourself to West Seattle. There are clinics in Ballard, Rainier Valley, Renton, North Seattle, Vashon Island, Lake City, Federal Way, Burien and more. Find the full list of locations and times here.

King County has one of the largest Master Gardener programs in the world. It started here, before spreading to all 50 states and many other countries. To find out more about becoming a master gardener, click here.