photo from flickr user paul (dex) // used under creative commons license
Technically, the first frost of the year already happened in New York City, though you wouldn't know it by looking out my window today- it's almost 60 degrees! But you'd better believe it, at night it gets cold out there. That's why it's time to make the decision about which plants need to be brought indoors, and which plants need to stay outside for the winter.
It might seem strange, but some plants actually do need to hibernate in the cold in order to survive. Think of it the same way that humans need sleep: if you never sleep, your body shuts down and you can't function. If some plants don't have their cold dormant period, they can only live for so long. I always want to bring all of my plants indoors because it makes me sad to watch them shrivel up in the cold, but I have to remind myself that this is an important part of their life cycle. (Don't forget that I grow my entire garden in containers, so I have full control over where my plants live.)
My outdoor plants are separated into three categories:
- Perrenials that are native to cold climates: These plants will come back every year as long as I take care of them properly and they have at least a few months of cold dormancy each year.
- Perrenials that are native to warm climates: These plants will come back every year after dormancy, but their idea of "cold" weather is southern California winters, not New York City winters.
- Annuals: Their lifecycle only lasts one year, so they have an internal clock that lets them know their time is up no matter what the weather is like.
Here's how I prep each of these plants for winter.
Perrenials that are native to cold climates
Planting native plants in your yard makes sense for lots of reasons, but a big reason is that they are biologically ready for the seasons without much prep work from us. My cold climate perrenials are going to stay outside all winter.
First, I make sure they're in the right location for winter because once it starts snowing, there's no way I'm going outside to move them. I take the pots down off ledges so they don't fall under heavy snowfall. I put my pots of spring-blooming bulbs near my windows so that when they start to sprout under the snow, I'll be able to see them.
Next, I double-check the condition of the soil. You can add some fertilizer or compost to your soil before winter, and when spring comes around you'll be starting with fresh fertile soil. I also add some mulch to trees and bushes. A full mulch cover regulates the soil temperature so that it takes longer for the soil to freeze, which means that your trees will last longer into the Fall/Winter season. Mulch also blocks out the falling weed seeds that are blowing around right now, so you'll have less weeds in the Spring if you cover your soil now.
Perrenials that are native to warm climates
I will admit that I buy plants that aren't really meant to grow in my climate. A good example of this is my carnivorous plant family- the Venus Fly Trap, Sundew, and Pitcher Plant. These guys will die if they don't hibernate in winter, but they can't handle the kind of winters we have in New York. They're also pretty delicate, so they would get damaged by winter wind, ice, and hungry animals. My solution is to put them in the refrigerator for 2 months a year. It's just cold enough to induce hibernation, but they won't freeze and I can totally control their environment.
The other warm-climate perrenial that needs to come indoors is my lemon tree. This tree will actually produce more fruit in colder weather, but "cold" for my lemon tree is 55 degrees. I put it in the window so it will benefit from the slight draft and chill, but it's still in a warm house with direct sunlight.
My annuals are all done for the season, but I still have to clean up after them. Most of my vegetable garden is annual plants, so once they've finished producing their fruit, they'll begin to die. This week I cleaned out my annual beds by pulling up any dead plants and turning the soil. I compost dying plant parts, but anything with seed pods goes in the trash: seeds will go dormant in your compost heap and then start to sprout when it gets warm. I don't want unplanned seedlings popping up in my garden next year!
After cleaning out the leftover waste from my annual plants, if I have any empty pots, I turn them upside down so they don't fill with water that could freeze and crack the pot.
If you want to keep your annuals for longer than one year, you can trick them a bit: just make sure they never flower and produce seeds. By pinching off the buds of annual plants, you can keep their foliage blooming (indoors) for longer than one season.