April To-Do List
Gardening tips from Town & Country
Take note of the blooming spring bulbs around you and plan your bulb garden now so you’re ready to plant in the fall.
Plant gladiolas, lilies, dahlias later this month for beautiful summer color.
Transplant, divide and relocate perennials. Water well after transplanting.
Fertilize established bulbs with liquid organic plant food.
Perennials and dormant roses can be planted this month. Hardy annuals such as petunias and pansies can be planted in late April.
Apply insecticide to roses.
Plant dormant potted and bareroot trees and shrubs.
Fertilize trees and shrubs.
Use systemic implants to help prevent borer damage in aspens, ash, and other trees.
Spray quaking aspens with systemic fungicide to prevent fungal leaf spot. Spray when leaves are about the size of a dime.
Check poplar, birch and green ash trees for borers. Look for small holes with sawdust coming out of them.
Prune most trees and shrubs (birch and maple should be pruned in late summer or fall).
Roto-till your garden plots and amend soil.
Tomatoes and peppers can be planted by mid-month if special covers are used to protect them from frost.
Peas, carrots, spinach and most other root and leaf crops can be seeded outside in late April.
Start new lawns or repair old lawns by overseeding.
Spray dandelions in late April before they start to bloom.
The More Ya Know
Gardening fun facts
  • The Idaho state tree is the Western White Pine, an evergreen tree that grows up to 80 feet tall on a straight trunk, with a low-limbed, tall narrow and pointed silhouette.
  • The official Idaho state soil is called Threebear, these soils occur on five to 35 percent slopes. They are a yellowish colored silty loam and the name comes from a creek in Latah County.
  • Carrots weren’t originally orange. The first cultivated carrots were purple, white or yellow. The familiar orange variety was selectively bred in the Netherlands in the 1600s, allegedly as a patriotic nod to the Dutch royal House of Orange. Yes, carrots were basically political propaganda.
  • Plants can “hear” caterpillars chewing them. Research shows some plants detect the vibration of insect feeding and respond by producing chemical defenses. In other words, they can’t scream, but they absolutely know they’re being eaten.
  • Lawns are historically a flex. Grass lawns became popular because only wealthy landowners could afford land they didn’t need to farm. A lawn basically says: “I’m rich enough to grow food nowhere on purpose.”
  • Talking to plants isn’t totally crazy. They don’t understand words, but they do respond to vibrations. Some studies show certain sound frequencies can stimulate growth, so your terrible singing might still be helping.
Garden Pest Patrol
Q&A with the Bonneville County Extension
A close-up of a Colorado potato beetle with a distinctive striped yellow-and-black shell and spotted orange head. It is perched on a fuzzy green leaf, which shows signs of insect damage.
Battling Beatles
Q: Last year I found a few Colorado potato beetles on my potatoes. How much damage do they do? Is spraying necessary?

A: “You don’t really need to control Colorado potato beetles unless and until they defoliate more than 10 or 15 percent of your potato leaves,” says Bob Stoltz, University of Idaho Extension entomologist.

If they reach that point, you really should try to do something about them. Handpicking works but gardeners also have some newer, “environmentally friendly” options to choose from. Try Bacillus thuringiensis, which destroys the beetles’ gut lining; neem oil, which repels them, interferes with their feeding and disrupts their growth patterns; or a spinosad product like Gardens Alive’s Bulls-Eye, which paralyzes them. Or, use more conventional insecticides like Sevin, diazinon or permethrin.

Every Rose Has Its Aphid
Q: I’d like to remove aphids from my roses without resorting to pesticides. What works?

A: You can blast them off with water or mist them gently with insecticidal soap, says Ed Bechinski, University of Idaho integrated pest management specialist. Either way is gentle on the environment.

Insecticidal soaps differ from body or dish soaps in their very specific carbon chain length, Bechinski says. “They’re intentionally designed to kill soft-bodied insects without harming plant leaves.” (Notable exceptions are glossy-needled plants like spruce trees and hairy-leaved plants like violets, which can’t tolerate the stuff.)

Unfortunately, insecticidal soaps lose their effectiveness as soon as they dry. Because they have no residual impact, you need to reapply them every three days to keep up with aphid infestations.

“The pluses outweigh the minuses,” Bechinski says. “Insecticidal soaps offer a huge margin of safety for you, me, our pets and the overall environment.”

Source: University of Idaho Coopertive Extension, Bonneville County

Back to Issue