Get Growing: Your garden on vacation

Summer is so beautiful in the Pacific Northwest that it seems a shame to go away, but if you do, don’t forget to set your garden up for success.

Seattle already receives barely perceptible levels of moisture in summer from rain, so our gardens depend on us for life support during our dry season from May-September. With weather patterns becoming so erratic, keeping your garden hydrated is even more critical to sustaining it during any heat dome that may roll in.

You may be saying, oh, my garden is shady and has never been irrigated or watered in summer. That’s what I used to say about the East-facing fence border in our yard. It’s got plenty of dappled tree cover, has moisture-retentive clay soil and plenty of tough mature shrubs and trees. For about ten years, I never watered that border, and still grew hosta leaves as big as my head. In the last few years however, we’ve had consistently low rainfall in winter and excess heat in summer and, in a new twist, spring. This created a double whammy of drought and heat (with a few extended winter freezing events thrown in) that overstressed even the hardiest plants in our borders.

Despite my extra ministrations watering in summer the last two years, I lost a massive lacecap hydrangea that predated us moving in, as well as a mature variegated willow Salix ‘Haruko Nishiki.’

So, the bottom line is, if you have mature trees and shrubs that you value and you haven’t had an irrigation system the last three years, they likely need about a month of water to catch up and rehydrate their roots and surrounding soil — please give them a good soaking (even several hours) right now. I’ll wait.

Other conditions that merit extra attention include:

• Young seedlings, cuttings, and recent divisions. One of the biggest causes of direct-sown seed-starting failure is letting them dry out. Their first roots are extremely thin and fragile and vaporize quickly without water. They may need water daily or more often depending on the heat and soil conditions.
• Fruiting or flowering plants grown for harvest. This could be your veggie and cutting garden plants as well as berry shrubs or fig trees – which with luck have some fruit swelling in August.
• Potted plants and hanging baskets, or plants in rockeries with little soil. Soil acts as an insulator and a hydrating sponge around plant roots, so pots don’t have as much moisture to draw upon, needing watering daily in hot weather.
• Plants in sandy soil – it releases water almost instantly. (Adding organic matter on top, whether compost, “Soil conditioner,” or natural bark mulch will help retain some water.)
• Plants without groundcover or mulch surrounding them to protect the soil from evaporation.
• Plants added to your garden or transplanted within the last two years. Similar to the seedling roots, plants need at least two seasons of regular watering to “establish” in their new spot.
• Plants that are struggling (unless, of course they are suffering from overwatering, as in a pot without sufficient drainage holes).
• Plants that love water and hate to dry out.  Examples include fuchsias, ligularia, and ferns.

Now that we’ve covered all the reasons to water, and which plants need some extra babying, here are some strategies to help them through your vacation.

If time and means allow, set up an irrigation, soaker hose, or sprinkler systems on timers – even if only for your most vulnerable plants. Early morning is the best time to water to avoid water evaporating in the heat and or water sitting on the leaves in cool conditions overnight which can promote fungal issues.

Other options to consider include digging in ollas – clay vessels that slowly disperse water over about a week or “plant nannies” in the form of wine or plastic bottles inserted into a clay cone in the ground. Ollas can be homemade by gluing two clay flat-bottomed pots together and sealing the bottom drainage hole with a cork or you can purchase them from various companies – you’ll need more for larger areas.

Another choice which looks silly but can do in a pinch – get plastic kiddie pools for groups of you potted plants and let them drink from the bottom up for ten days or so.

Mulching with bark, grass clippings, shredded leaves, or straw will help retain a lot of moisture in the soil for in-ground and potted plants.

You can also hire help or bribe neighbors to hand-water (note you may have to offer to watch their Bernese Mountain Dog the next time they go away).

No matter which you choose, before you head to the airport, drench your garden and pots with a loooonnnnggg watering to give it a good reserve from which to draw.