With the weather going from cold to hot to warm back to cold again, we are often asked what is growing in our garden? The best way to find out is to see for yourself, but we asked our Horticulture expert, Adriana Quiñones, how plants can survive during these fluctuating weather patterns.
-Are there plants that survive all year round?
Plants are categorizes as annuals or perennials. Annuals complete their lifecycle in one season- they germinate from a seed, make a flower, make a new seed, and then dies. This actually happens in the growing season, so even shorter than a year. A few plants are biennial- they basically do the same thing but it takes two years to form the flower. But after it blooms and set seed, it will also die. Perennials have some way of continuing to reproduce multiple times without dying. Some plants only survive by having their roots live over each year. These are called herbaceous perennials. Others maintain the whole plant and we call these woody perennials. You call them trees and shrubs! Some will keep their leaves year round. These are evergreens and some lose their leaves and are called deciduous.
-How do plants adapt to the climate?
We live in a temperate climate. That means we experience a change in the seasons that is not extreme on either side. There is also polar (cold) subtropical and tropical (hot). There are a few other categories but this mostly covers them. Plants adapt in various ways depending on where they grow. In our zone, we can get pretty cold 10-20 degrees on average. Plants here adapt by removing the parts that will get damaged by the cold, such as leaves and aboveground parts. The remaining parts that are above ground, make “plant antifreeze”! The plant basically alters the composition in their cells to prevent freezing so the plant can survive the winters. Here is a technical version of this: Plant cells survive sub-freezing temperatures by adjusting their solutes, proteins, and membrane lipids in order to withstand desiccation and to avoid ice crystal formation. This stage of life cycle of the plant is called dormancy, but really it is just an altered state of growing.
-How much does snow affect plants?
If the plant has already made the needed changes in the cells to survive winter, than snow is not a factor. What is could be a potential danger with snow is that it is heavy; accumulation may case branches of trees and shrubs to break. This is why you may want to brush off heavy snow from some plants if they seem weighted down. A positive aspect of snow is that it acts as an insulator. So if you have a slightly tender plant, one you’re not sure has the right adaptations to survive the cold, the snow cover may help it make it through the colder temperatures. You may have seen this phenomenon when there is a lot of snow cover but the air is extremely cold. All the plant part above the snow dies but the part covered will grow again in the spring.
-Does covering the plants in the cold actually help the plant survive?
Covering plants can be a good idea. Just like snow, this extra layer helps to insulate the plant. Plants are adapted to a certain region and when the temperatures exceed what the plant is adapted to, it will die if not protected somehow. This is also important if we have a warm spell and the plants start to come out of dormancy. The new growth does not have the same protection from the altered cell composition and will not be protected from the cold. So if a cold spell comes after growth started, those new plant parts will freeze. Covering them after they started to grow may help them survive a cold night. Also, if the plant does get damaged from the cold, this can lead to more problems, including death at a later time as the damaged part is more susceptible to disease attack.
-What else do we do to ensure the plant’s survival during harsh climates?
Plants are resilient. The best thing to do is plant plants that are locally adapted to the place you are trying to grow them. If you try plants that are adapted to either cooler or hotter climates, you will need to fuss over them more than ones that grow well in this area. Also, make sure plants stay healthy by mulching them, treating them for disease and insect problems before it gets bad and watering well during the growing season. A healthy plant is much more likely to survive the cold than an unhealthy one.
-What about when it gets hot? How do we protect the plants?
You can set up a shade structure but for most, this is impractical. It is better to make sure that the plant remains well watered. When it is hot or windy, the plant will lose water at a much faster rate. By making sure it has plenty of water, the stress of losing water will be reduced on the plant. Things like homes, brick walls, fencing and concrete driveways, all reflect heat and by planting away from these structures, you will reduce the heat stress on the plant. But remember, this same thing may be what helps a marginally hardy plant survive the cold winter also.
The most important part is to pick the right plant for the right location. Native plants are already adapted to survive both our cold winters and our hot humid summers. Plants that thrive in a climate similar to ours will also do well here. But don’t be afraid to try something new. That is half the fun of growing things. And if they don’t survive, at least you tried it.