You should really give your gardens a good cleaning out this fall — both your vegetable gardens and flower gardens. The extent of your cleaning depends partly on your personal taste and partly on the number of pests in your garden.

“We used to leave a lot of perennials up for the winter,” William Cullina of Coastal Maine Botanical Gardens said in a telephone interview earlier this month, “especially the grasses and the flowers with seed heads. We did this partly for aesthetics and partly so the birds could eat the seeds.”

But in recent years, as soon as the grasses and perennials begin to turn yellow, the garden workers cut them down to the ground or wherever is appropriate for the particular plant.

“We have found that when we leave things up,” Cullina said, “it is like putting up a vacancy sign for the voles. The voles move right in and just breed all winter, and in springtime they devour your garden.”

Without a comforting home in the gardens, the voles will go elsewhere.

Another reason that Cullina likes to clear out all of the gardens in the fall is that spring is always busy, and that major task is already done before the busiest time. And with the plants cut down, the wind will blow a lot of the leaves off and into the woods, so they don’t have to be raked.

Cullina has enough on his plate as it is, so he will not want to add work. He has been director of horticulture and plant curator at the gardens since 2008 and acting executive director since August, although he said, “the horticulture department is sort of running itself.”

Another reason for cutting down flowering plants in the fall is to prevent unwanted seeding.

“We didn’t cut down the turtlehead (Chelone) last year, and this year we had about 15 million seedlings just downwind from the primary plants,” he said.

There are a few exceptions to Cullina’s cut-back-everything rule. He said that plants like lavender, hyssop and other woody mints regrow in the spring from buds above the ground, and they do better if left standing.

Cullina said there isn’t really much else that has to be done in the gardens for fall cleanup and preparation. The staff puts on a lot of Nutri-Mulch — a product from New England Organics in Unity — in the spring, so the plants don’t need any mulching to protect them in the fall.

Other tasks in the fall are to stop irrigating in September and to remove leaves in areas where gardens are located under the trees.

Volunteers at Coastal Maine weed regularly during the growing season, but if you are less than diligent about keeping the weeds out of your gardens, it makes sense to weed one last time about now — just a little bit before the ground freezes.

You are probably less busy now, and you don’t want the weeds to continue growing in the early spring before you get out to deal with them.

Nancy and I — like Cullina before his vole problem — have always left grasses and seeded perennials up all winter because we like looking at them. And we haven’t had a serious vole problem in the past. So we’ll have to have a discussion about whether to cut down or leave standing sometime before the first snow flies.

With the vegetable garden, it’s a lot simpler: Get all of the dead and dying material out of there.

This is especially true of potatoes, tomatoes, squash and other plants that are susceptible to blights, mildew and other fungi. You’ll want to get the diseased plants out of your garden and probably off your property before winter hits.

Some people leave some root crops in the garden for harvesting during the winter, and that is perfectly fine. Those gardeners should mulch the vegetables heavily so the soil around them does not freeze and they can be pulled easily from below the snow.

But almost all vegetables have stopped producing with the first frost, so it is time to get the remnants cleaned up.

Tom Atwell can be contacted at 791-6362 or at: [email protected]