The garden is a mess – overgrown and weedy, full of invasive plants.

It’s not your fault. Maybe it’s a summer home, and you never made it to Maine last year. Or you’re helping out a friend, neighbor or family member who is getting older and has been unable to keep up. Maybe you’ve just purchased a house that has been abandoned for a while – lucky you, in this market.

Whatever the cause, the mess has to be dealt with. But be prepared. No one can do this in a day, a week or probably even a month. And if you think you have fixed the worst of the problems, expect major work next spring, when the roots and seeds you left behind begin sprouting again.

The first thing to do is get rid of the invasive plants. There are different grades of invasive. The worst are the 33 plants that the state has deemed illegal to sell in Maine.

Several of the invasives – garlic mustard, Norway maple, Japanese barberry, Japanese honeysuckle, multiflora rose and burning bush or euonymus alatus – occasionally show up on our property, though we have been working to get rid of them for decades. It doesn’t help that our neighbors still gladly grow many of them. Remember, just because it is illegal to sell them, it does not mean that homeowners have to remove them.

One of the worst invasive plants, swallowwort, isn’t on the list because nobody ever thought it was worth selling.

Some invasives, like garlic mustard and bishop’s weed, just pull out. They will probably come back, but you can pull them out again. Bittersweet, which can wind itself up dozens of feet on desirable trees, is also fairly easy to pull out. You can recognize it by its orange roots.

Others, like Norway maple, Japanese knotweed and honeysuckle, can be dug out if possible, but probably you will just cut down as close to the ground as you can. They will resprout, but cut the sprouts as soon as you see them. If the plants don’t produce leaves to feed the roots, eventually the roots will die. You can get rid of knotweed by mowing regularly, but wash the mower well (including the blade) each and every time or you will spread the pest.

Many years ago, we got rid of a patch of honeysuckle and multiflora rose by cutting them to the ground in late September and painting the cuts with full-strength Roundup. The method was suggested by a respected Cooperative Extension educator, and it worked. I have never sprayed Roundup, but this method was described as safe. Roundup is now illegal in some municipalities, but not statewide. With what we now know about Roundup, I probably would not do it again. But it is a legal option in some places. And no, you cannot “paint” invasives with vinegar, lemon juice or other organic liquids to kill plant roots. You’ll know immediately if someone invents something like that.

After invasive plants, there are good plants in wrong places. The past two years have produced more acorns than I have ever seen in successive years. My wife, Nancy, and I have pulled up thousands (I am not exaggerating) of oak seedlings this spring, ranging from an inch to a foot tall, in the vegetable gardens, flower gardens, lawn, brick walks and patios.

I heard in a Zoom talk over the winter that a chickadee’s brain size increases 30 percent each winter so the bird can remember where it hid its food. Squirrels don’t have that talent, so as insurance, they bury acorns everywhere. All the ones they fail to remember and eat grow into unwanted oaks. You might also find some unwanted red maples, but I keep them if possible. (Red maples are a wonderful native that can be tapped for maple syrup, though they produce less than sugar maples, and they have beautiful fall foliage. I remove seedlings only when they are too close to buildings or established, desirable plants.)

If you have what you think is a good plant in a wrong place, you can dig it and move it to a new spot, but remember that you are going to need to water that plant for the rest of the growing season. And watering means at least a gallon of water a day for 10 days to two weeks and then an inch of water a week for the rest of the growing season.

Next, it is pruning time. If you have tall trees that need pruning, call an arborist and get on a waiting list – they are busy this year. Untrained people can get hurt putting up ladders to cut limbs. The State of Maine has a list of licensed arborists – check whether or not that “nice man with a chain saw” has a license, including insurance.

If branches are dead, crossing, rubbing together, touching the house, blocking paths or the driveway, or just look ugly, and if you can reach them with a pole saw, cut them away. I know I have written in the past that spring-flowering trees and shrubs should be pruned after they bloom and the others pruned in late winter. This is a gardening emergency, and the rules don’t apply.

Next comes weeding. I’ll be writing more about that next week, but here are the garden-renovation basics: If you know it is an undesirable plant or if you don’t want any plant in that location, dig it out – even if it takes a shovel.

If you are unsure whether or not it’s a weed – and with some plants, people have debated that point – leave it alone, let it blossom, and decide after it goes by or next spring whether or not you want it in your garden. Thinking about spring, keep in mind that while you’re digging, you may turn up bulbs. Just replant them, and next spring you’ll learn what you have.

Pat yourself on the back. You’ve done enough for this year – unless you have created a bare spot and you’ve a plant in mind to put there.

Tom Atwell is a freelance writer gardening in Cape Elizabeth. He can be contacted at: tomatwell@me.com.