The lone voice of horticultural reason

What Is Plant Culture?

Any hobby capable of enchanting one for a lifetime does so through slowly revealed intricacies. A fly-fishing fanatic starts out buying exotic flies from austere catalogues then evolves to tying his own flies with exotic feathers bought from even more austere catalogues. A golfer can hone her skills for 10 years without lowering her score then hear one tip concerning her chin that cuts three strokes from her game.

So it is in gardening. Learning plant culture-what conditions a plant likes to grow in-plays a big part in becoming a better gardener. What hooks us in this hobby is that within this topic lie thousands of intricacies. No gardener will ever know them all, but as the western suburbs have just spent another week doing their best Sahara Desert impersonation, let’s finish up the finer intricacies to watering.

Last week’s column made the point most plants and vegetables feel good with an inch of water per week. It’s a nice general rule to remember, but it’s not without its nuances. Splash a hose across a rain gauge and you’ll fill it an inch in less than a second. So can we water our plants a few seconds at a time? Of course not. An inch of rain may come down over your entire yard in the course of a week during two or three hard storms (at least it used to). That’s a true inch of water, and will seep down eight to ten inches into properly prepared, well-drained soil. To duplicate this in the garden with a hose and watering wand one needs to water a good thirty seconds around the base of a tomato plant or medium-sized perennial.

Now all you need to learn to move up one rung as a better gardener is which plants in your garden exist outside this rule. Here are the ones from my garden:

Campanula glomerata (Bellflower) – One of my favorite perennials, but one of the first to drown from excessive moisture. Pick up the pace a bit when watering around them.
Astilbe (False Spirea) – Here’s the opposite. Astilbes are in vogue right now, which means new owners are killing them like mad. They need much more than an inch of water per week, even in the shade; plunk them down in full sun (which you shouldn’t do) and you’ll need to water them every three days or they’ll shrivel and die by fall.
Liatris (Gay-Feather) – A little of both here. Will welcome ample moisture during the growing season but ease up on the watering in late fall and early spring or the corm will rot. Must winter in sandy loam.
Iris – I only water bearded iris every other time, as they are prone to moisture rot. Truth is, they’re quite drought tolerant. Siberians, on the other hand, welcome ample moisture prior to blooming, then around half an inch per week after bloom.
Ligularia (Golden Ray) – Will thrive in a bog, so what does that tell you? A fabulous yellow spiked bloom that your neighbor doesn’t have. My favorite, “The Rocket,” blooms best with morning sun and afternoon shade. It wilts in hot sun but keep the soil evenly moist and it’s fine.
Hot Peppers – The secret to boosting potency in hot peppers is to let the soil dry out completely between waterings, and I mean to the point of surface cracking and early wilt. Think about the climate they’re native to and it starts making sense.

And that’s it. All the rest-95% of my garden-gets an inch of water per week. OK, I skipped over groundcovers, and azaleas and rhododendrons deserve a separate column, but for the most part it’s that simple. If I have five minutes to kill waiting for my son to find his baseball glove I’ll flip on the hose and water the astilbe and ligularia, maybe the bleeding heart while I’m at it. I’m careful not to hit the bellflower too hard, etc.

What are the intricacies to watering your garden? The easiest way to learn is to buy plants from people who cheerfully explain everything you should know about the plants’ culture. Next week I’ll introduce you to some of my favorite people.

Don Engebretson
The Renegade Gardener