What to do in your garden in April

Planning and Planting

New plants. Among this year's introductions are Agastache x 'Ava', a hummingbird mint with raspberry red blooms; Anthemis tinctora 'Susanna Mitchell', a creamy white daisy with lacy gray-green foliage; Aquilegia caerulea v. ochroleuca, a white-flowered form of Rocky Mountain columbine; Clematis scottii, a shrubby clematis with small, bell-shaped purple blossoms; Lavandula angustifolia 'Buena Vista', a reblooming English lavender; scarlet-flowered Penstemon pinifolius 'Nearly Red'; and Zauschneria 'Mountain Flame', which has scarlet-orange blooms. All are winter-hardy in Sunset climate zones 2b-3b (Denver, Boise, Salt Lake City). Order from High Country Gardens ( or 800/925-9387).

Potted Easter lilies. When your Easter lily (Lilium longiflorum) finishes blooming indoors, you can transplant it into the garden; it will often come back for several years, though blooming will shift to late summer. Plant the bulbs 6 inches deep in good garden soil, then water and fertilize regularly.

Time-tested perennials. In trials conducted by Colorado State University, several perennials were standouts for the high plains of the Rocky Mountain region: Astrantia major 'Margery Fish' bears soft pink flowers in August; bear's breech (Acanthus balcanicus) carries purple-and-white flowers in June; Coreopsis verticillata is covered with small yellow daisies from summer to frost; Heliopsis helianthoides scabra sends up yellow-orange daisies in midsummer; Lavatera thuringiaca displays cup-shaped pink flowers on 2- to 4-foot-tall plants; Lysimachia ciliata 'Purpurea' has purple foliage and yellow flowers; and Sidalcea 'Party Girl' has pink flowers resembling tiny hollyhocks.


Attract beneficial wildlife. As frogs, toads, salamanders, and snakes emerge from hibernation, encourage them to stay in your garden and help control pests. Set shallow bowls or birdbath basins on the ground, and keep them filled with fresh water.

Cope with salt-laden soil. In parts of the intermountain West, soils can have high levels of salts due to naturally occurring minerals, irrigation water, or fertilizers. The concentrated salts may show up as a powdery white crust on the surface (a soil lab test can confirm the problem). One short-term fix is to flood the affected soil with water to flush the salts out of the root zone. The most natural solution is to plant salt-tolerant flowers and shrubs. The list includes Apache plume (Fallugia paradoxa), artemisia, Colorado blue spruce, 'Stella de Oro' daylily, juniper, Jupiter's beard (Centranthus ruber), lilac, mock orange (Philadelphus), saltbush (Atriplex species), Sedum 'Autumn Joy', and sulfur flower (Eriogonum umbellatum).

Spruce up birdhouses. Remove birdhouses from their perches, discard old nests, and wash out interiors with a bleach solution (4 tablespoons of bleach to 1 gallon of water). Remount houses 6 to 20 feet above the ground in a quiet part of the garden. If you don't have a birdhouse, Audubon Workshop ( offers a range of models.

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