The lone voice of horticultural reason

Spring Perennial Care

This year’s true, cool spring weather has been a blessing to our west suburban gardens. Most of the perennials in my neighborhood have entered the first week of June fuller and bushier than I can recall in recent years. There are echinops, veronica, ligularia, sedum and various phloxes in my garden that I have never seen so stout and robust at the close of spring.

We’ve grown used to these “blink and they’re gone” springs the past few years when it seems the furnace is still needed in mid-April, then the kids are swimming in the lake mid-May. Perennials hate that. Here they’ve just poked theirs heads above ground after somehow surviving a Minnesota winter and in a scant few weeks it’s 80 degrees, placing tremendous stress on plants. This year they have had ample time to emerge, get accustomed to the slowly warming soil and develop strong new root growth. Now the heat and even longer days of June will start signaling the early and mid-season bloomers to start heading in that direction at a natural, even pace. Blooming this year across the board should be fantastic, right into the fall asters, mums, boltonia and sedums.

We did finish May more than a few inches short of average rainfall, however; now that temperatures have hit the 80s a few times the topsoil is getting very warm and what your plants don’t drink soon evaporates. Most perennials and vegetables need about an inch of water per week, and that’s a lot more than just five seconds over a plant with a hose. The key to watering anything is to water less often, but water deeply. Watering lightly simply puts moisture into the top few inches of soil, and roots only go where there’s water. A shallow root system from improper/light watering stunts growth, lessens bloom, makes the plant more susceptible to disease and increases your chances of turning perennials into annuals come next spring.

Buy a watering wand that screws on the end of your hose and turns the stream into a gushing shower. For a big perennial-let’s say a clump of phlox we should have divided this spring but didn’t-it will take at least a minute with the head of the wand very close to the ground, in the center of the clump, slowly around the edge and then repeating a few inches out, to get water not just throughout the root system but below it. I have one perennial bed that’s about 40 square feet-that’s not very big-and it takes me a full 15 minutes to water it, if that’s a guide. I water it every six days if it’s hot with no rain. Water the ground, not the plant, water in the morning if possible (I usually water before work) so splash dries off leaves quickly, and never use your lawn sprinkler to water garden beds. If you can’t find time to do it properly by hand, consider installing a drip irrigation system, teaching and paying a neighborhood kid (boys love it), or don’t grow so darn much.

Develop deep root systems in your perennials by watering deeply and they will stand up much better to the intense heat of July, reward you by living longer and may even forgive you for slipping off on vacation during a week with no rain in the forecast.

Don Engebretson
The Renegade Gardener