Weathering drought

This May I posted about my suspicion that I was over-watering my garden, and why that was environmentally unsound. The post prompted me to cut back drastically on watering via our sprinkler irrigation system. Until this summer, I had the system programmed to deliver water twice weekly to each of twelve irrigation zones.

    I was aware that most of my established trees, shrubs, and perennials were well adapted to dry spells during New England summers. They needed frequent watering in their first two years while they got settled and developed a generous network of roots. After that, they should be able to thrive without supplemental watering, except at the driest times. 

Established plants should be able to cope with dry summer conditions

    So why didn’t I cut out the watering after plants entered their third year in the garden? One excuse is that I was continually adding new plants, so often a bed with older plants also contained newcomers. But I think the real reason was that in my heart, I didn’t really believe that my babies could make it through the summer without a regular soaking two or three times per week.

Would the balloon flowers perish without watering?

    After challenging myself with that blog post, I decided to focus on watering areas where I’m growing vegetables, annuals, and newly planted and perennials. In the rest of the garden, I’d stop irrigating. If individual plants needed water, I’d water them by hand.

I'm still watering a bed of vegetables and pollinator plants

     Overall, I’m surprised and pleased at how well the garden is looking this year with about a third as much irrigation as I gave it during the last few summers. My area is experiencing a mild drought. This weekend we were 5 inches behind our average precipitation for the year, despite heavy rains this week. Yet the garden is chugging along, not noticeably daunted by the dry conditions.

Doing fine without watering

    Over the years I did reduce watering in some of the irrigation zones that contained only mature plants. A red-leaved Japanese maple (Acer palmatum ‘Atropurpureum’) and mostly evergreen shrubs in a bed of vinca (Vinca minor) in the front yard got less and less irrigation. This year this zone is getting none, which highlights an issue with my planting plan.
     
     Two mountain hydrangeas (Hydrangea serrata) that I planted in the front yard don’t tolerate dry spells the way the other denizens do. The hydrangeas wilt dramatically after three days without rain or irrigation. 

Lacecap hydrangea starting to wilt

This year, instead of taking that as a cue to irrigate the whole bed, I’m watering the hydrangeas with a watering can. That seems to suit them fine. 

     I could have avoided this complication if I’d thought to group plants that need lots of water together in one irrigation zone, as a Xeriscape gardener would do. That way I could have lavished water on one section close to the house and let the rest of the yard fend for itself.

     By taking parched conditions in stride, the garden is teaching me a lesson. I’m seeing that it’s OK to let my plants live as they would naturally, including tolerating some dry times. 

Coneflowers unfazed by summer weather

Dry and thirsty

The recent heat wave following on a months-long drought displays the many mistakes I made regarding water when I designed my garden. In hindsight, it’s easy to see better choices I should have made.

    Most basic was plant choices. Xeriscape, a water-conscious approach to garden design, provides guidelines for selecting plants that don’t need supplemental watering. Some tips: smaller leaves generally need and lose less water, grayish or fuzzy foliage usually means a plant is drought-tolerant, low-growing plants avoid drying winds, and plants with a scent, such as lavender, produce aromatic oils that help plants hold onto water. I did end up with some plants with each of these characteristics, but not out of any conscious plan.

Gray, fuzzy leaves of lambs' ears (Stachys byzantina) conserve water

    Next, I should have grouped plants based on their water needs. Putting thirsty hydrangeas next to water-sipping catmint, with its small gray leaves, might have looked nice, but it meant I under-watered the hydrangeas and probably used more water on catmint than it needed—though it didn’t complain.

 

Hydrangeas need a lot of water

    Then there was my choice of irrigation method.

Sprinklers lose water to evaporation

The sprinkler system we installed was standard for our city, but I could have saved on evaporation by using soaker hoses, which sweat droplets of water, or drip irrigation, with small emitters that deliver water precisely to the spot its needed at the base of a tree or shrub.

    My rain barrel is a small step toward collecting rain to irrigate the garden. 

The rain barrel is great--when it rains

I wish I’d thought to install an underground cistern to store all the rainwater that falls on the roof before I planted my garden. If I had, in an average year the cistern could have supplied my garden’s irrigation needs. This is certainly not an average year, though. To irrigate with rainwater, you have to have rain, and this year that’s been scarce.
 
    So at this point, my garden is looking sad and parched. 

A forsythia wilting outside the range of the irrigation sprinklers

With a guilty conscience, I supplement scheduled irrigation from the sprinkler system with evening use of a rotating sprinkler to revive wilting plants in areas the automatic system misses (evening watering is recommended to minimize evaporation). 

     We get our water from the Quabbin and Wachusett reservoirs in western Massachusetts, and our water authority hasn’t imposed a watering ban so far. Not so lucky are gardeners whose water comes from town supplies, nearby rivers, or wells on their own property. I can only imagine how painful it would be to watch cherished plantings die from lack of water.

    If I ever build a new house, I’ll put in that underground rainwater cistern before I start planting, and I’ll push for a graywater system too. That would collect water from sinks, dishwasher, clothes washer, and shower to reuse for irrigation. The city of Las Vegas has this all worked out long since. 

     In the meantime, I’ll make sure I dump water from the sink on garden beds when I can instead of letting it flow down the drain, and I’ll think about less lawn and more drought-tolerant native plants for next year.

Cucumbers on the deck benefit from any spare water from the sink