May 01, 2021 5 min read

As the saying goes, “April showers bring May flowers,” and it really couldn’t be more true here in Portland. As the weather warms, and the skies clear, plant growth explodes and everything is in bloom! Outdoor gardening season has arrived! (Happy dance!!)


Last month, we suggested weeding and watching for pests. As May arrives, these practices become more important. Look for signs of insect damage. Grab weeds while they are still easy to pull out. 

Those little white moths are about to lay eggs in their favorite vegetable plants like cabbage after which you will notice holes in the middle of the leaves made by cabbage worms. Spray the damaged plant with BT or Spinosad (both are beneficial bacteria that paralyzes the insect, but is not absorbed by the plant and has no effect on humans or pets). 

Holes in the middle of leaves or wilted tops of plants could also be due to cutworms.  If you notice other young plants sawed off at the soil line, inspect the ground surrounding the damaged plants for tiny, pellet-shaped black droppings. You might also spot worm poop on the leaves if the cutworms have crawled up higher onto the plant.  Choose Sluggo Plus to control cutworms but don’t let pets ingest.  

A slime trail on foliage with edges of the leaves missing is indicative of slugs or snails.  Slugs and snails find basic Sluggo an irresistible meal (by taking away their appetite, they glide off and die.)  Basic Sluggo is not harmful to people or pets if used lightly as recommended.  

A glob of spittle on the stems of plants has a tiny green spittlebug inside.  This cute little insect is not harmful to plants unless there are many on one plant, which is rare.  They are a fun thing to show young children by taking your finger through the spittle and letting the green spittlebug sit on your finger to look at how large their eyes are, then letting them go.

Aphids are tiny brown, black, yellow or most commonly green soft-bodied insects that show up on tender new growth or flower buds to suck the sap from plants.They usually occur in colonies as they are born pregnant and can reproduce within hours.  Best to catch the first few!  Heavily-infested leaves can wilt or turn yellow because of excessive sap removal. Remedy by hosing with water, squishing by hand and/or spray with Captain Jack’s Dead Bug Brew.

Continue prevention measures such as spraying apples and pears with Orchard Spray, a type ofparaffinic oil that may be used as a growing season spray, dormant spray (no leaves) or delayed dormant (green tip) spray to control overwintering eggs of red spiders, scale insects, aphids, bud moths, leaf roller, red bug, codling moth, blister mites, galls, whitefly, mealy bugs and other insects. Highly recommended for use on fruit trees, shade trees, shrubs, ornamentals, roses and vegetables.

May is also an excellent time to prune your rhodies, azaleas and camellias as their blooms fade. If they need to be kept smaller, now is the time to trim them back. If you haven’t already fertilized this spring, sprinkle and water in EB Stone Rhody, Azalea, and Camilla Food around the drip line, which is perfect for these acid-loving shrubs, as well as blueberries, fuchsia and evergreen conifers. 

Give your plants the boost they need to leaf out, flower and grow by fertilizing with an organic fertilizer around the drip line and watering it in deeply.  Hydrating deeply and feeding plants before the heat of summer gives them a stronger position to withstand stress—like preparing for a marathon or extended physical exercise.  This is especially true for rhododendrons and azaleas—the Azalea Lace Bug goes after these plants when they’re stressed in lots of summer sun without enough deep watering.

Edible Gardening:

Pass the peas, please! Vegetable Gardening Season has arrived! It’s time to harvest peas planted in Feb/March. If you haven’t already, get those veggie starts going! Vegetables and fruits planted now will be ready for harvest in time for your summer table.

Tomatoes are quite popular right now. We have 75+ varieties in stock, along with everything you need to have a successful crop this year.Read more here. We highly recommend usingEB Stone Tomato and Veg Food, as well as a product like Bonide Rot-Stop in order to prevent blossom end-rot, and grow healthy tomato plants. 

At this point, soil temps should be above 70 degrees, which is the ideal temperature for ground planting tomatoes, eggplants, sweet potatoes, melons, and squash. Use a soil thermometer to be safe. You may need to wait until mid-month for less hardy starts like cantaloupe and watermelon. 

Peppers, beans, Brussels sprouts, kale, onions, cucumbers (we have a grafted variety already putting on small cucumbers!), and herbs like sage, rosemary, and thyme can all be planted right now as well. Also look to sow seeds of green beans, okra, melons, and eggplant. 

Outside Plants and Flowers:

It’s planting season for annuals, perennials, shrubs and trees which will add beautiful color and pollinator options to your garden through the season.  Look for a combination of plants that will flower into Fall to increase the available pollen and nectar to native insects and hummingbirds.  Be sure to add Organic E.B. Stone Sure Start fertilizer for a fast boost to all new plants with lots of long term beneficial mycorrhizae and slow release food.   

May is the perfect time to plant warm-weather annuals like impatiens, petunias, bacopa, lobelia, sanvitalia, mecardonia, verbena, bidens, salvia, geraniums, coleus, sweet potato vine, calibrachoa, alyssum, heliotrope, fuchsias, cuphea… many colors and textures to play with in the landscape or containers. By mid-May, it is time to plant for summer color with tuberous plants such as gladioli, begonia and dahlias.  Zinnias usually need to wait till end of May temperatures.

Plant trees before summer heat and practice deep watering from the beginning—frequency not as important as quantity of water.  Look for fruit trees and shrubs like rhodies which are finishing up blooming, but will be valuable color or produce for your landscape next year. Give a boost to shrubs with fertilizer if you haven’t already this spring.  

Roses begin to blossom in May.  If you haven’t pruned yet, now is the time…however, it will delay the bloom time—sometimes necessary to remove dead wood and crossing branches to have a healthy bush.  Not too late to plant roses for beautiful and fragrant summer bouquets!  Start deep watering with roses now before the heat of summer to ward off disease and insect issues.  Feed existing roses with E.B. Stone Rose & Flower Food once a month through summer for best results.