An Expert Explains How to Over Winter Plants

Kathleen Roberts
Over Winter Plants

Many gardeners, from beginners to the more experienced, have questions concerning how to over winter plants. Garden expert Danielle Ernest from Proven Winners brand plants addresses these issues in this exclusive LoveToKnow Garden interview.

How to Over Winter Plants

Winter is the time when most plants rest and recover from a busy year of making your yard gorgeous. Here are some helpful tips from Danielle Ernest to help you help your plants.

Interview with Danielle Ernest

What Is Over Wintering

LoveToKnow: What does it mean to over winter plants?

Danielle Ernest: The definition of over-wintering means to care for a plant (annual or tropical) that typically doesn't make it through the winters in your zone by bringing that plant into your home - living area, basement, garage - to keep it alive from year to year. Because if left outside, it would not be able to survive due to the level of coldness in your growing area.

LTK: What plants are best suited for over wintering?

DE: Plants that are typically over-wintered are plants we treat as annuals but are actually tender perennials such as geraniums, impatiens, sweet potato vine, etc. The other category of plants that are over-wintered are tropicals such as bananas, philodendron or any plant that would be typically sold as an indoor plant for your region of the country.

Danielle Ernest

For instance, when I lived in Michigan many gardeners would use spider plants and Boston ferns to decorate their outdoor living spaces. Those plants are considered tropical in Michigan and would not survive the below zero winter temperatures. They would need to be over-wintered indoors.

Really, these plants don't need special treatment. It is up to gardeners if they prefer to over-winter plants indoors or if they prefer to buy those annuals and tropicals from year to year. Personally, I prefer to buy annuals from year to year. I don't have a lot of room to over-winter plants in my house and I have animals that tend to eat any plant that I bring into my home. So really, it is up to the individual. I believe it is often a personal challenge that experienced gardeners set for themselves. Everyone likes to push the limits - I always did this with my garden in Michigan when it came to sun/shade and zone requirements.

How to Do It

LTK: What are some basic steps for protecting plants through the winter?

DE: For perennials and shrubs that you are keeping outdoors in the ground during the winter, you really do not need any protection. This is the time that plants take to go into dormancy and refuel on energy for the next spring - similar to what animals do when going into hibernation. Shrubs and perennials in containers may need some special treatment to last the winter.

The tip I give to beginning gardeners is to know your zone. All you need to do is put your zip code into the search box on the Proven Winners site. For instance, I am in zone 7B where I now live in Washington state. That means when I go to the garden center, I need to look for plants that will survive in 7B or lower (6, 5, 4, etc). These would work in my garden. Once you become more familiar with your garden, there will be spots where plants that normally wouldn't survive, say a zone 8 plant, can survive because there is a micro-climate being created, maybe from the heat of your home.

Bringing Plants Indoors

LTK: How are plants prepared for bringing them indoors and what kind of care will they need indoors for the winter?

DE: Typically, most homes do not have enough full sun window space to bring plants indoors successfully. This, however, is not a reflection of the gardener that you are. Plants need to receive proper lighting, water and fertilizer to grow throughout months where we typically do not get long days due to the time of the year (fall and winter). The low humidity is a contributing factor to why some are unsuccessful as well. Many gardeners that over-winter plants have assisted lighting with grow lights, small greenhouses and sunrooms to be successful.

First off, it is important to get your plants indoors before your first frost. If the leaves are damaged by frost, it is going to be hard to get them to recover and may not be worth the effort.

When bringing plants indoors from outside, you will want to inspect the plant for insects or disease. If there are signs of insects or disease, you will want to use a spray of your choice to get rid of them before bringing the plant indoors. You should also remove any diseased leaves or stems. It is almost better to be more cautious then not on this topic. I would consider spraying for insects even if you don't see them at that time because once they are indoors - they are indoors.

Bring container plants inside.

Since the plant will experience stress during the transition, it is best to select plants that look extremely healthy for better success. If the plant is in a container, the transition is extremely easy, but if they are planted in-ground the plant must be dug up and planted in a container. This is when I say, "Forget it, I'll just buy it next year," but to each their own. When digging up this plant, make sure to get a good portion of its roots and plant it in a container with fresh potting soil that has fertilizer incorporated in the mix.

After planting, make sure to give the plant a good drink of water. This means water until you see water coming out of the drainage holes. I would consider letting the plant get used to its new container home for a couple days outdoors in a lower lighted area before moving it inside. For plants that have been in containers all summer, water thoroughly and give it the recommended fertilizer rate.

Once the plant is brought indoors, it is important to place it in a location that gets as much sun as it was receiving outdoors originally. Plants may be placed in a greenhouse, sunroom, bright window or under grow lights if needed.

I would not recommend digging up the plant, placing it in a different light level and shearing it all at the same time. The amount of shock a plant goes through may influence whether it lives or dies. After the plant has been in the home for a couple weeks, I would then decide to cut-it back. If the foliage continuous to look healthy, then proceed with cutting back the stems ½ inch. Make sure to clean your cutting instrument between plants with lightly soapy water or rubbing alcohol to prevent the spread of disease.

To help with low-humidity, use a shallow dish and fill with clean gravel and water. The evaporation of the water will provide your plant with humidity. Also, a spray bottle can be used to mist the leaves a couple of times a week instead of the above recommendation.

While your plants are indoors, fertilizing them is not necessary unless you notice that the plant is growing quite a bit. If that is the case, lightly fertilize them only once a month or so. Watering will only be necessary when the top of the soil is dry to the touch. Then water until a small amount of water comes out of the drainage holes - you do not want to over water the plant. If you have a hard time determining when the plant needs to be watered, I always recommend using a tray and filling it with water so that the plant can drink the water as needed by sucking it up through it roots. This method is most useful for me.

Typically, plants that are over-wintered indoors tend to stretch to the necessary light source. In the spring, when the plants are transitioned back outdoors a light shearing can take place again.

Other Tips

LTK: What else should gardeners know about over wintering plants?

DE: It is important to not let worries about over-wintering affect you as a gardener. Over-wintering plants is difficult - even nurseries and greenhouses lose plants during the winter months, but that is all part of gardening. If you fail, try, try again.

Even those with degrees in horticulture can have black thumbs, but that doesn't stop us from trying. Believe me, I am one of them. Gardening is all about the learning process and you can really learn a lot from others around you. Don't be ashamed to ask for help.


LoveToKnow would like to thank Danielle Ernest and Proven Winners for taking the time for this interview on how to over winter plants.

An Expert Explains How to Over Winter Plants