May is prime planting time. Just about anything you want to plant can be planted now. It is the month when the largest selection of plants is available in nurseries and garden stores. Trees, shrubs, vines, ground covers, flowers, vegetables, summer flowering bulbs, lawns, all kinds of fruit plants and trees. Bare root plants should have been planted by April. But since almost all plants are available in containers nowadays, they can even be transplanted in full leaf and full bloom.
Move Spring Flowering Bulbs
The end of May is a good time to move spring flowering bulbs such as daffodils and tulips while there are still leaves above ground so you can locate them. If bulbs have become too thick, or are overgrown with shrubs, dig them up and replant them as soon as the leaves begin to turn brown.
Plant Annual Flowers between bulb leaves
You do not have to wait until your spring flowering bulb leaves are gone to plant annual flowers. Simply dig holes between bulb leaf clusters and plant your flowers.
Long-blooming Perennial Flowers
Plant breeders have made significant progress in recent years in developing perennial flowers that bloom all summer long. Two of my favorites are Geranium Rozanne and Coreopsis Moonbeam. Unlike annual geraniums, Rozanne has sky blue flowers that begin blooming in early May and continue until October or November. Plants grow about a foot high. Moonbeam Coreopsis has thread-like foliage and one inch lemon yellow daisy flowers that cover plants with color from late May through until frost. There are another dozen or more perennials that I use regularly in landscape plantings for my customers.
Most of you are not aware that I spent 10 years of my career working for a flower seed company. During the 23 years I spent at Ricks College (now BYU-Idaho) I designed and planted acres of flower displays in the Horticultural Display Garden. Give me a call if you would like some advice or help adding color to your landscape. Remember I offer free landscape consultations.
Controlling Insects on Fruit Trees
We have a number of insect pests attacking apples, pears, and cherries in the Vancouver area. Some of these pests become active in early to mid-May. A new organic insecticide called Spinosad is effective in controlling all of these pests. Adding horticultural oil to the spray improves effectiveness. To control codling moth larvae (worms) in apples and pears, begin biweekly applications in mid-May. Continue to apply every two weeks until early August. Spray for cherry fruit fly maggots every two weeks from early June to harvest. Another way to prevent wormy apples and pears is to place Codling Moth Traps in trees to trap the adult male codling moths, preventing female moths from laying fertile eggs. This method is less effective if you have neighboring fruit trees without traps or sprays.
Flowers in Containers
Flowering baskets and tubs are becoming increasingly popular for decks, porches, and patios. I prefer larger containers such as minimum 10 inch hanging baskets and 12 inch pots and tubs. They do not dry out as quickly as smaller containers. Make sure planting containers have large holes for drainage.
The best potting soils allow water to move into the soil quickly and have peat moss or other materials which hold moisture. I like to add water holding crystals such as “Soil Moist” to help retain extra moisture. Soil mixes are now available which already have moisture retention crystals mixed in. Many potting soils contain slow release fertilizer which is also good. This usually lasts 4 to 6 weeks when more fertilizer should be added. If you are using a mix without fertilizer or last year’s potting soil, add slow release fertilizer such as Osmocote before or when you plant.
Most nurseries and garden stores have a special section of potted flowers especially selected for containers. Many have trailing or spreading growth. Non-flowering plants with colorful leaves are often mixed in. A single upright plant is often added to the center of large tubs and pots to give some height.
Select plants according to their sun/shade tolerance. If containers are on the east or north sides, or under an overhang, shade tolerance is important. Plants for containers facing south or west or without any shade need to be sun tolerant.
Most plant labels indicate whether a plant prefers full sun, part shade or full shade. Some of the best plants for shady locations are pansy, viola, begonia, impatiens, lobelia, fuchsia, browalia, coleus, lamium, nierembergia, and variegated ivies grow well in the shade. A taller plant in the center of tubs is effective.
For sunny areas, some of the most popular flowers include diascia, petunia, ivy geranium, lobelia, pansy, bacopa, calibrachoa (million bells), alyssum, lobelia, trailing snapdragon, trailing verbena, lotus, and sweet potato vine. Some good upright plants are salvia, euphorbia, dracaena spikes, snapdragon, and ornamental grasses.
Some of the best plants for single variety containers are ivy geraniums, impatiens, hanging basket begonias, fuchsias, bacopa, calibrachoa (million bells), and trailing petunias.
Most of my tubs are mixed plantings. I like to plant at least 2 or 3 plants of each kind per container. I place like plants across from each other or at equal intervals around the container. I place plants so that their soil balls are almost touching each other to get a more immediate effect.
My favorite fertilizer for containers is Osmocote or similar coated, time release fertilizers. I mix fertilizer into the top inch or two of soil. Organic fertilizers are also slow release. You may need to make a second application in mid-summer. If you use liquid fertilizer instead, apply some every week.
Apply Slug Bait around Flowers and Vegetables
Slugs and snails are plentiful in our moist climate and can quickly devour newly planted flowers and vegetables. They hide in the soil during the daytime and feed at night. Apply slug bait around perennials such as Hostas and when planting new annuals and vegetables. Baits containing metaldehyde are the cheapest. Baits which contain iron phosphate are safe to use around children, pets and wildlife. Bait which is not eaten by slugs and snails will degrade and become part of the soil. Deadline is another very effective product for snail and slug control.
Raise Lawn Mowing Height
As weather warms it is good to increase the height of your lawn mower. Lawns mowed at 1½ inches or higher will be more resistant to heat and drought. Grass root growth is in direct proportion to top growth. Longer and thicker roots can absorb more moisture from the soil.
Keep Ahead of Weeds
Warm weather weeds are just starting to grow. Weeds are much less work to control while they are small. Besides hoeing and pulling, there are several other good methods of controlling weeds. Bark and compost mulches are effective in preventing light from reaching weed seeds, reducing weed growth by up to 90%. Weed preventer chemicals such as Trifluralin will prevent new weeds from germinating around flowers and vegetables. Preen is the best known brand, but other, cheaper brands are available. Sprinkle granules right after you have weeded or planted new plants. Casoron is another weed preventer which can be used around woody plants only. Casoron will also kill existing grassy weeds. Weed barrier fabric can be spread on the ground around trees and shrubs to act as a barrier to weeds. It is porous and allows water, nutrients, and air to pass through.