“When can I plant?” people ask me every spring. Answer: It depends.

“Where do you live?” I ask them. “And what do you want to plant?”

This year’s mild weather had folks itching to start veggie gardens and plant trees way back in February. For some cool-weather veg, and for perennials like trees and shrubs, that’s no problem. In fact, as long as the soil isn’t frozen, get those trees and shrubs in the ground, let their roots start soaking in water and nutrients, to make their parent plant strong like bull before the heat and dry set in. In fact, the one time not to plant perennials is in mid-summer, when roots won’t have time to spread and adapt before the summer’s oppressive heat. You’ll barely be able to water enough to keep the plant from going all crispy and sad by August.

It’s still early enough to plant perennials, but do it soon. And if you’d like to put a few annuals in the ground or in pots, go for it: after April 15, it’s generally considered frost-safe in our zone. (Although you might wait a few more weeks before planting particularly cold-sensitive annuals like basil and tomatoes—give it until May 1 or so.)

Mom and I have a yearly tradition we call the “Annual ‘Annual Day'”, usually around one minute after tax day, in which we endeavor to fill the 30 or so pots I have scattered around the yard. We’ve planted Japanese maples in a few of these, but the rest demand a palate of brilliant annuals. Every year, we simplify, decreasing variety to maximize effect—a single sweep of deep purple and pale green pleases me more than a profusion of everything. Here’s what the pot garden looked like in July of last year:

Persian shield, sweet potato vine, and sedum (right)

Last week we spent nearly two full days filling pots with our simple favorites: pink impatiens and caladiums in the shade pots, Persian shield and pale green potato vine in the sun pots, and hot-pink vinca in some small plastic pots we painted—they resist the fiercest drought and soldier on, so they can manage small pots without a lot of whining and wilting.

The Persian shield-potato vine combination has become our hands-down favorite. Persian shield, Strobilanthes dyerianus. The scientific name brings to mind some fallen Spartan defender of Thermopylae; and the common name just reinforces my imaginings in that regard—a final defense against Xerxes’s hordes, a stately royal-purple weapon of last resort.

The plant is a stunner, and I cannot fathom why it’s so difficult to find in garden stores: Deep purple leaf veined with olive green and silver, and it looks regal paired with pale green potato vine—Ipomoea, another name evocative of the ancients. Our hero Stobilanthes’ wan lover perhaps? I imagine a tragic storyline for poor Ipomoea, a fair maiden rendered even lovelier by grief; mourning becomes her. Becomes her too much, it seems: inevitably, she attracts the notice of lusty Zeus, who deceives her and defiles her in the form of a spike of Miracle-Gro.

But I digress.

What is an annual, anyway? 

If you have to plant it every year, it’s an annual. If it comes back every year, it’s a perennial. But it’s not 100% that simple. I remember a friend asking me if an ornamental grass she’d planted was an annual or a perennial. “It’s an annual here,” I said. Purple fountain grass is cold-hardy only to about 20 degrees or so; so it might be perennial in Florida, but it’s a de facto annual here. It’ll die if the mercury dips below 20.

She was pretty annoyed. “Why didn’t the tag say ‘annual’?” she said, irritated that she’d spent money on a single-season grower. In a sense, it did say so. In the cold hardiness section, the tag read “20 deg. F.” In plant geek code, that means “I am an annual here.”

Cold hardiness isn’t your only concern as you read the hardiness zone tags. Be sure you also know how much heat a plant can take. Certain lilacs might be hardy to minus 20 or more, which is why they thrive in Russia. But can they manage 100 deg. F? Not as such; although there’s an exception: Miss Kim is a lilac cultivar that can take the heat. And it’s named after me, so of course, I have 6 of them.

That’s it. Just two questions. Lamest FAQ ever. Got any more? Post them.

Related post: My favorite annuals

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