Here are some ecologically sensitive landscaping practices that I have learned about recently for Seattle landscaping.

Consider the sun’s path through the sky and how the sun heats not only your home in the summer and winter but also heats up paths which reflect that heat onto sensitive plants. Planting shade trees in strategic spots can provide shade and screening. Remove narrow concrete paths and replace with dark bark mulch. The mulch doesn’t reflect light and doesn’t have much nutrient value for weeds.

Planting density can affect weed growth when gardening. If shrubs, perennials and groundcovers grow into a dense mass there is less light and area for wind-blown weed seeds to take hold.

Drip irrigation placed at the base, root balls and trunks can help get larger shrub groupings the water they need with less water loss due to wind and evaporation. When designing irrigation systems; the placing of drip emitters or soaker hoses, locate them at the interior of planting beds where dense root masses can absorb the water, they are shaded by vegetation and protected from wind.

A yearly application of compost and mulch, or compost/mulch combinations can hugely help improve soil quality. Over time rocks and pebbles are pushed to the surface and the nutrient rich layer of topsoil gets deeper and deeper. A thicker topsoil layer encourages plant roots to reach deeper, thus holding moisture longer and eventually needing less irrigation.

Compost and mulch can also be applied to lawns. The deeper the grass roots extend the longer the grass will remain green in the summer and the healthier the lawn will be; preventing weeds from taking hold.

There are many methods for on site management of rain water. Options to disconnect down spouts from the city storm water system include cisterns, rain gardens, gravel and drain rock swales, and impervious paver systems. Be sure that big storms can still flow to the storm drains without flooding sidewalks or onto neighbor’s property. More information can be found at www.seattle.gov/util/rainwise.

Outside my kitchen window grows a Mock Orange (Philadelphus virvinalis) the scent from which has been wafting in for weeks. I know that as a designer I always incorporate scents into a garden, trying to provide a surprise for each season and pleasure for the owner. But this shrub I did not plant. It was there when we moved into the house, in a side yard to which I seldom go, and it grows happily in benign neglect, right up to the eaves. But the serendipitous pleasure it brings our family each year has prompted me to think again about other plants that provide beauty appreciated by senses other than sight. So to start, here are some great smelling additions for the seattle garden.

Winter: Hamamelis x intermedia ‘Arnold Promise’, Sarcacocca hookerana humilis, S. ruscifolia

Spring: Choisya ternate, Daphne odora, Wisteria floribunda, Clematis armandii

Summer: Lonicera japonica, Jasminum polyanthum, Philadelphus coronarius

Fall: Cercidiphyllum japonica – the leaves smell of cinnamon and apple, Itea iliciflora

And don’t forget the herbs, especially the old standards: the mints, parsley, rosemary, and the thymes.

Baxter

Seattle gardening and landscape maintenance begins with proper watering. When trying to determine the frequency and duration of watering periods, always consider the soil conditions, the weather conditions and the plant itself. Healthy plant roots need oxygen as well as water. In clay soils, water can drain very slowly and deprive the plant of the oxygen its roots need. During the summer, the heat and lack of rain can dry out your plants. Windy conditions can also dry out plants, thereby requiring more water than expected. New plants require substantially more water than established plants.

It is best to think of watering in two ways. You can either sprinkle or flood (soak). Different plants like different watering techniques. The best time to water is early morning. This helps to prevent disease by allowing plants to dry completely before the cooler evening temperatures arrive.

Established lawns (2 years old or older) need 1” of water per week. This is normally accomplished in our region naturally from November 15^th through March 15^th. Lawn roots are relatively shallow but you want to promote deep rooting. Lawns also dry out quickly, so it is best for an established lawn to be sprinkled 3 times a week. Set your irrigation clocks to make sure your lawn is receiving 1” of water per week.

Established trees (2 years after installation) require water monitoring. When established trees need water they prefer a complete soaking. If the soil is not damp at a 6” depth, your tree needs watering. Water until the soil is wet to that 6” depth. During hot weather, soaking the root ball once every week is usually sufficient.

Established shrub beds need .5” of water per week. This is normally accomplished in our region naturally from November 15^th through March 15^th. Maintaining a 2” layer of mulch helps to keep the water from evaporating too quickly and thereby reduces water usage. Sprinkling is generally fine for most plants. Set your clocks to make sure your beds are receiving .5” of water per week.