Summer in the Pacific Northwest is so beautiful that it would be a shame to leave. But when you do, don’t forget to set your garden up for success.
Seattle already receives minimal moisture from rain during the summer, so our gardens rely on us during the dry season from May to September. With weather patterns becoming so unpredictable, it’s even more important to keep your garden watered to sustain it during a potential heat wave.
You may say, “Oh, my yard is in the shade and has never been watered or watered in the summer.” That’s what I’ve always said about the east-facing fence border in our yard. It’s covered in plenty of shade trees, has moisture-retaining clay soil, and lots of hardy, mature shrubs and trees. For about ten years, I never watered that border, and yet it still grew hosta leaves as big as my head. In recent years, however, we’ve had consistently little rainfall in the winter and excessive heat in the summer and, most recently, in the spring. This has resulted in a double whammy of drought and heat (and a few extended freezes in the winter) that has overwhelmed even the hardiest plants in our borders.
Despite my extra watering measures in the summer of the last two years, I lost a huge lacecap hydrangea that had been growing before we moved in, as well as a fully grown variegated willow Salix ‘Haruko Nishiki’.
So the bottom line is: If you have valuable, mature trees and shrubs and have not had an irrigation system for the past three years, they probably need about a month of water to rehydrate their roots and surrounding soil – please water them well now (even for several hours). I’ll wait.
Other diseases that deserve special attention include:
- Young seedlings, cuttings and recently divided plants. One of the most common causes of direct seed failure is drying out. Their first roots are extremely thin and fragile and evaporate quickly without water. Depending on the heat and soil conditions, they need to be watered daily or more often.
- Fruit-bearing or flowering plants grown for harvest. These can include your vegetable and cut garden plants, as well as berry bushes or fig trees – which, with a bit of luck, will bear some fruit in August.
- Potted plants and hanging baskets or plants in rock gardens with little soil. Soil acts as an insulator and moisture-retaining sponge around plant roots, so pots cannot absorb as much moisture and need daily watering in hot weather.
- Plant in sandy soil – this releases water almost immediately. (Adding organic material such as compost, “soil improvers” or natural bark mulch will help retain some water.)
- Plants without ground cover or mulch that protects the soil from evaporation.
- Plants that have been added to your garden or transplanted within the last two years. Similar to the roots of seedlings, plants require at least two seasons of regular watering to “establish” themselves in their new location.
- Plants that are doing poorly (unless, of course, they have been overwatered, e.g. in a pot without adequate drainage holes).
- Plants that love water and don’t like drying out. Examples include fuchsias, ligularias and ferns.
Now that we’ve covered all the reasons for watering and know which plants need special care, here are some strategies to help them survive your vacation.
If time and resources allow, install an irrigation system, drip hose or sprinkler system on a timer – even if only for your most sensitive plants. Early morning is the best time to water to prevent water from evaporating in the heat or sitting on the leaves overnight in cool conditions, which can encourage fungal infections.
Other options you can consider include burying ollas – clay pots that release water slowly over a week or so – or “plant helpers” in the form of wine or plastic bottles inserted into a clay cone in the ground. You can make ollas yourself by gluing two flat-bottomed clay pots together and plugging the bottom drainage hole with a cork, or you can buy them from various companies – you’ll need more for larger areas.
Another option that looks silly but can work in a pinch: Get plastic wading pools for your groups of potted plants and let them drink from the bottom up for about ten days.
Mulching with bark, grass clippings, shredded leaves or straw helps retain a lot of moisture in the soil of in-ground plants and potted plants.
You can also hire a helper or bribe your neighbors to give them water (note that you may have to offer to watch their Bernese Mountain Dog the next time they are away).
Whatever you decide, before you leave for the airport, water your garden and pots slooooolowly so that they have a good water reserve.
