How to use plants to cool your house: planting for energy efficiency

Wise planting can help shade a house in summer.

I have a south facing wall of the house. This wall and small yard area get wickedly hot under the summer desert sun. My backyard also has a west facing house wall which runs along my entire backyard. This also has sun beating on it for many hours every day. The heat, of course, moves into the house through the wall and the roof in spite of the insulation.

I need to have some kind of cover along those baking expanses- either with a deciduous tree, or with some sort of vine which I would grow up a trellis beside the house. My neighbor has a young tree which will eventually shade the southwest part of my house, but not for at least five years. So, I decided I would grow vines up the house, but not against the house. Some of the most popular vines like ivy or trumpet vine often damage a house in the process of growing along a wall.

The idea is to have plants that make shade during the hot summer and keep the house cool but then lose their leaves so the less intense winter sun can warm the walls. Here are links to examples of the information that is often available on electricity supplier’s websites about using plants for shade.

Landscaping for Energy Efficiency

How to Plant Trees to Conserve Energy

Grapes grown on a trellis. Image from Vicki's Garden Tips.

I will put up trellises that will be self-supporting, so the vines won’t touch the house. When I was younger, I saw the Amana colonies in the Midwest. These were early religious settlements that were clever and efficient with their farming practices. They put grape trellises growing parallel but not touching the walls of may of their houses. This allowed for shade against the house, without damaging the house, and it grew a crop in an otherwise unused space. They could squeeze between the house and the arbor to harvest the grapes.

I will do something similar on the south-facing side of my house. Because of the wine industry, there is a ton of research about different grape varieties, their cold-hardiness and fruiting. The Colorado State extension has findings on successful varieties for the HOT summer/cold winter successes from an agricultural research station in Colorado. California grape research is all over the Internet too, so there is no lack of info on growing grapes.

I will need varieties that can take the heat of a southern exposure and I will probably put annual vines there, too, until the grapes plants are larger. I might put morning glories, or a climbing bean or maybe a small fruited vine in the squash family like gourds or a vining cucumber. Bush cucumbers are more common, so I will need to look specifically for a variety that suggests growing on a trellis or fence. If any of these annual vines grow up from seed in the hot sun, they will be fine as long as I keep them well watered.

Along the west side, I've decided to put vines on a temporary trellis which I can tear down. So what comes to mind for my west wall is hops –yea, the beer ingredient. It’s very easy to find in nurseries these days since home beer brewing is becoming more popular. It is a fast-growing, wiry perennial vine that is a bit prickly and will twine around anything.

Hops fruit on the vine. Picture from Logee's.

I grew hops at my old house and know that they are tough and will cover my new trellis in a short time. However I don't like the smell of the leaves when you touch them, though many folks do (I don’t like a beer that is too hoppy, either), so cutting down the vines is always a job I dislike.

At the old house, it would cover the back fence every summer in about 3 to 4 weeks. I like that speed – much faster than most vining plants. It is pretty in a leafy way, but its flower is small and inconspicuous so don’t plan on anything but soft lime to mid-green. It does make an interesting fruit, which is the part that is used in beer making, and these persist on the plant through mid-winter. During winter, the whole plant turns a soft red-brown, and provides some winter interest.

My solution is to plant them so that they are climbing disposable trellises and to put them in a place where I won’t brush against them.

I will grow them up disposable plastic fencing. You can find this fencing at most big box stores or garden shops. The kind I am familiar with is gray or black, has ½ - 1 inch squares and is sold as bird protection cover for cherry trees,  or for temporary fencing. It is about 3 feet wide, very lightweight and not very expensive so I won't feel bad about taking it down and throwing it away.

Along the west side of my house: These trellises are disposable fencing, held down with T-posts and attached at the top to hooks which are attached to the house. When winter comes, I will disconnect them from the posts and the unhook them from above and toss the whole thing in the trash. After a summer of hot sun, the fencing will be damaged, so I can justify my non-thrifty disposal.

The trellis along the southern wall of my house with the dormant grapes. The trellis is a ranch fence panel and electrical conduit pipe. It is attached to the house at the top.

Hops die to the ground every winter and re-sprout with enthusiasm in the late spring when the soil warms up. They can be aggressive, if allowed to spread unchecked along the ground.

I have to guide the first growing sprouts so that they grow where I want them to go. But after that I can leave it on its own, and just beat it back in several years when its underground growth takes it to places in my garden where I don’t want it. If you plants hops, be aware of this spreading, because they shouldn’t be ignored if you garden in a small space.

I will leave the vines up for visual interest until winter when the sun drops low. And then, I can just clip the dead stems off at the ground, rip off the temporary fencing and throw the entire mess away.

These are the grapes in early June. I have planted gourds next to them because it will obviously going to be a number of years before the grapes grow enough to shade the house. The corn poppies are an early blooming annual that reseed themselves with abandon and which die and are removed by July.

Here are the hops in just over a month in mid-June, covering the fencing. I took the temperature against the house in late afternoon in the shade – 90 degrees, less than the air temperature at that moment. The side of the house in the sun was 109 degrees. Notice the shade on the hops on the right. This is shade made by my apricot tree, which in a few years will cast enough shade to keep the backyard much cooler – and may give me some fruit as a bonus.

Hops will spread easily, and new babies will sprout up nearby. If you don’t want too many hops plants, dig these new babies early. They are attached underground to the main plants so use a sharp shovel to cut them apart about halfway between the 2 plants. They transplant well, so you can pass them onto a friend.

How to get started with container gardening

Some tips on buying or making your own container gardens
Spring flower displays in stores always make me think I need to have more container plantings in my life. The truth is though, I am not attentive enough to them to keep them watered and fertilized. So I usually have one pot, and it lives by my door so I am reminded to give it a drink. It is usually red geraniums, because that was my Mom’s favorite, and because they are forgiving of irregular watering. If I am inspired, I will add something that drapes down the side of the pot, or maybe alyssum, tough and ever-blooming.

You can grow herbs and vegetables in containers.
Image from Gardenwise.

Container gardening has a number of advantages. If you have no land to garden in, you can grow your summer garden in a container. 

There are lots of vegetables that have been developed to grow in pots, like patio tomatoes and some squash and cucumbers. Vegetables will always do best if they have several hours of sun and regular water. Most nurseries have plants and seed choices to help you get summer satisfaction.

Many herbs do well in containers and it is often recommended that you plant robust mints in a big pot in your garden, so their amazing tendency to spread can be controlled. 

Containers are also portable if you think about size ahead of time. When one pot starts to look less than sterling, you can replace it with another one that looks better, or even something newly planted.

Pictures of clustered containers with a theme fill pages of gardening and women’s magazines and make me again have to fight off the urge to have more containers in my life.

From Patio Design Ideas

There are clever ways to put drip systems into or onto containers, but I am not yet familiar enough with automation to go that route. 

From Gardening from the Ground Up

If you are like me and won’t water daily, then get succulents. These plants are adapted to store water in their leaves and to be able to take hot sun and less water. They do need attention though, so don’t ignore them completely.

The horticulture industry has developed some really fabulous succulents like ice plants, which bloom in a myriad of colors. There are also many, many choices of sedums, which are chosen for their foliage, not their flowers. The leaves on sedums vary by shape and by color, so you can have quite a lovely, multi-colored container garden without a single flower.

If you like the colors of the innumerable annuals like petunias, which do so well in containers, you can either buy the containers ready-made or make them yourself. The advantage of planting them yourself is that you get to pick the colors and textures that appeal to you. It shouldn’t be intimidating to make a hanging basket or container garden. Important points to remember:

• Get a pot or container that has a drainage hole. Remember that water will drain out, so make sure you have a saucer under the pot so there won’t be water damage wherever you put the pot.
• Get a good quality potting soil. Don’t use soil from your yard. Growing in pots is different than growing in real soil. Real soil drains differently and also adds a lot of weight if you want to move the containers later.



Petunias are prone to overgrowing their
containers and neighboring plants.
From Cozy Home

• Pick plants that have the same moisture and sun requirements for each container you plant. Mixing succulents and marigolds in one pot is not good for either of them.
• Keep in mind how big each plant will get by mid-summer. Petunias can grow over smaller flowers.
• Consider adding foliage-only plants. There are some nifty grey plants as well as coleus which have leaves as their main attraction.
• If you can, take your pot to the nursery and put your selection together in the pot. This will give you an idea of how the plants look all together AND keep you from over-buying.

To plant your container garden:

1. Fill your pot almost full of potting soil and water it well. This is something that is rarely recommended but if you are planting large containers or pots, it is hard to be sure that the deepest soil is really moistened. This means you will be working with wet soil but the soil will compact a bit when it is wet, so you will have to add a bit more dry soil on top once you start to plant. You don’t want it to be sopping wet, just moist. Mix it with your hands and see what it feels like. Be warned! You will get dirt under your fingernails unless you are wearing nitrile gloves, which are the only ones I have found that you can still feel through.
2. If your potting soil has dried out (not uncommon if you have had an open bag over the winter), it may take several waterings over a period of hours to rehydrate it. You can tell if it has dried out because the water runs out almost as fast as you pour it on. You may need to soak the pot full of soil in a bucket to catch the water and let it stand. After it is wet throughout, pour the bucket of water onto your garden and put the pot somewhere it can drain for a couple of hours before planting in it.
3. Ease the new plant out of its nursery pot. If you can see lots of roots, gently break apart the root ball. Dig a small hole where you want the plant to go.
4. Don’t bury the plant deeper than the existing soil line.
5. Repeat with all your plants.
6. Cover any visible roots with additional soils and water gently. If soil moves off the root ball, add more soil. If you planted any of your new plants too high in the soil, you can pull them out and dig a deeper hole.
7. Put the pot outside in shade for a couple of days. Ease it into the sun, then into its final location.
8. Water it with a dilute solution (about half strength) of soluble fertilizer on the 3^rd or 4^th watering and once a week after that.
9. Water with full strength soluble fertilizer once a month.
10. Dead head (cut off old flowers) every so often. This keeps everything looking tidy and encourages more blossoms

If you bought a ready-made container, see 7-10 above.

Pinterest is full of beautiful designs if you want to get inspired, and feel free to send pictures of your containers in to share.