The two best perennial vegetables come into their own in May, a great time for planting as well as eating them.

Asparagus is a classy vegetable, justifiably popular in high-end restaurants, whether prepared with sauces, shaved into salads, or just lightly steamed and served with butter and pepper.

Rhubarb is more down-home, a spring tonic fresh from the garden. Yes, rhubarb is technically a vegetable, although most people use it as a fruit in pies, jams, chutneys and sweet sauces.

My wife, Nancy, and I have grown asparagus for almost 30 years. Hands down, it is my favorite vegetable and one of her favorites, too. For the past couple of years, our production has declined – with gaps appearing in the row of asparagus we planted in the sunniest part of our garden. A couple of weeks ago, I put in 25 new plants to guarantee sufficient asparagus in the future.

You plant asparagus by buying roots, also called crowns. We initially planted Mary Washington, a heritage variety. With Mary Washington, you get both male and female plants, which pollinate each other and produce seeds. Those seeds will occasionally sprout, so we have several asparagus plants 20 feet away from the original asparagus row in the vegetable garden and – more interesting to me – in a lilac hedge about 40 feet away. I assume the seeds were left by birds and thrived.

The 25 asparagus crowns I planted this year were Jersey King and came from Fedco, the seed cooperative in central Maine. (That won’t help you now, as Fedco’s deadline for buying this year is past.) Jersey King is all male plants, which means you get no seeds and no surprise plants in your garden. Because the plants don’t spend energy producing seeds, they produce more bountiful stalks.

Planting asparagus is a bit of work: You dig a trench at least 6 inches but preferably a foot deep in rich, well-drained topsoil. The initial instructions 30 years ago said to put a mound of manure at the bottom of the trench for each asparagus crown, spread the roots around the manure and then just barely cover the crowns with topsoil. The instructions with the Jersey King did not mention the manure, but I used it anyway because it worked last time, and why mess with success.

Plant the crowns at least 18 inches apart in the row. If you are doing multiple rows, keep the rows about 3 feet apart. The stalks tend to move a bit over time as the roots multiply – which I know only because my once-straight row of asparagus is now crooked – you do want to give the asparagus room to spread.

During the first year, cover the sprouted spears with topsoil until the trench is again level with the rest of the garden. Tempting as it may be, under no circumstances should you cut and eat any of the asparagus the first year. The plants must feed the roots or they won’t survive the first winter. Keep the asparagus bed weeded. Fertilize with manure, compost or organic fertilizer in the spring – every year. The catalogs say that asparagus lasts about 20 years, but with care it can last longer.

Ideally, you shouldn’t harvest any asparagus the second year, either, but a couple of spears just to make sure you like the vegetable won’t hurt much. Asparagus usually starts producing early to mid-May, and we will harvest until the peas start producing in early July. We cut the plants down in late fall, but it would be fine to wait until spring.

Some people think the thinner asparagus stalks are younger and tastier, but since I know that roots planted at the same time sprout spears of different thicknesses I can prove they aren’t younger, and I believe they aren’t tastier, either. If you mound up asparagus with sand or mulch and cut it before it sees any light, you can get white asparagus (known as spargal in Germany, where it’s wildly popular and celebrated each spring), even though they sell crowns specifically as white asparagus. To me, white asparagus does not look appetizing.

Rhubarb is a lot easier. For starters, I don’t know anyone who has ever purchased a rhubarb plant. The plants divide easily, so you get them from friends or relatives. We got ours, like we did many other plants, from Nancy’s grandmother. We have divided it several times since to give to friends. Johnny’s Selected Seeds in Winslow sells several varieties of rhubarb, and it is available at some garden centers and seed stores, as well.

Online planting instructions say to keep the rhubarb weed-free and in full sun. Ours is in part sun, is weed free and does quite well. I’ve seen rhubarb live – with fairly thin stalks – in hay fields, so I’d say it can survive some weed pressure, too.

Our rhubarb produces just a bit later than the asparagus, mid- to late May, but that might be because it gets more shade,

If you do buy crowns (like asparagus, rhubarb roots are also called crowns), you’ll want to plant them in the spring. If you are taking plants from an old clump of rhubarb, you can transplant it anytime from spring to September, as long as you water it regularly. Don’t cut any rhubarb the first year, but you can the second. You can harvest until July.

One large clump of rhubarb is enough for our two-person household, but other people probably eat more rhubarb than we do.

Rhubarb leaves are poisonous. Stick to eating the stalks.

Once a rhubarb plant reaches 3 years old it might, if healthy, produce a flower stalk that, if not cut off, will then produce seeds. If your prime purpose is getting rhubarb to eat, cut those flower stalks immediately. Nancy and I like the way the blooming stalks look, however, so we don’t always do that. We’re perverse that way.

Tom Atwell has been writing the Maine Gardener column since 2004. He is a freelance writer gardening in Cape Elizabeth. Contact him at 767-2297 or at [email protected]