Wondering how you can do your landscaping and yard work in a more gentle-on-the-earth and sustainable way? Janet Hartin, horticulture advisor and author with the U of California, has given over 1000 talks on sustainable landscape topics, and our local horticulture group was one of them last month.
Below are some of takeaways from her talk, which focused on incorporating plants suitable for your climate, conserving water and improving poor soil. Other important sustainable methods include preventing and reducing pests without relying on chemicals and encouraging wildlife (I’ve written quite a bit on the latter – here is my last post on our yard attracting more wildlife )
But first, why consider some of these changes – what are the benefits of sustainable landscaping?
- Save money
- improve garden health
- protect water quality
- protect wildlife
Selecting Plants more Sustainably
- Stick to plants from your climate zone
In California we pride ourselves on the ability to grow nearly everything, but I have plenty of examples of why we’ve gone to more plants native to our region – they DO do best, while the coleus I brought from my relatives home in Minnesota made it until late summer, and the cypress we purchased that is native to the foggier California coast finally succumbed to our harsher inland temperatures.
- Consider plant location
In a heat island such as a parking lot, the same plant can require 50% more water than it does planted in a yard. I’ve noticed the same ceanothus species planted next to our curb is 1/3 the size of two that are 10 and 15 feet away and surrounded by other plants. “The same tree that is water efficient in a yard can struggle when surrounded by asphalt, which can heat the area up to 150 degrees in July in the desert due to reradiated heat,” says Hartin.
- Plant trees on the south and west side of your home
This provides shade and can reduce air conditioning needs by 10 to 15%.
Lowering Water Needs
Here in the West we rely on irrigation so many of these tips are for irrigation users. Aside from the obvious solutions of repairing broken nozzles so you’re not watering sidewalks or the street, Hartin provided other suggestions to save water:
- Hydrozone your landscaping
This means planting plants together with similar irrigation needs and water appropriately.
- Water established garden and landscape plants deeply and infrequently.
We have killed more plants from overwatering than underwatering (especially my houseplants…) Here in the West many people overwater their landscaping. Water as long as you can before runoff occurs and as Hartin said to give plants just enough water that they look good. Watering this way encourages deep roots. “Water annuals to at least six inches, shrubs about a foot and trees at least 1-1/2 feet deep,” says Hartin. You can use a trowel, shovel, or soil probe to see how far down the dry soil begins or one cost-effective alternative is probing with an old-style coat hanger that has been straightened.
- Convert non-groundcover and turf areas to drip irrigation
Instead of a spray system that wets soil between plants, a drip system reduces soil evaporation by applying water directly to the root area.
We’ve removed the little lawn we had left and are seeding it with buffalograss and blue grama grass, which require 1/2 the water of our former grass. I’m currently pulling the remaining old grass and weeds that come up – will keep you posted.
- Add a 2-3 inch layer of wood chips or other mulch and don’t over fertilize
Too much fertilizer creates weak flushes of growth and increases water requirements. We prefer compost for most plants.
Nurture and Protect Your Soil
Keeping soil healthy by adding compost and avoiding soil compaction are key, says Hartin. Here are some specifics.
- Avoid soil compaction: Heavy equipment can compact soil, creating poor drainage and no aeration — so plants often decline and die.
- Before planting, evenly mix compost into garden soils that are high in clay or sand: This increases the drainage in clay soils and improves the water holding retention in sandy ones. The caveat? “Don’t add compost to tree planting sites; roots may grow in circles, never leaving the safe cocoon of the compost to venture into the poorer surrounding soil,” said Hartin.
- Grasscycle – recycle your clippings: Did you know that annually a lawn produces 300 to 400 pounds of clippings per 1000 square feet a year? Either use a mulching mower that allows them to drop back on the lawn where they provide nitrogen and lower water needs, or compost them.
- Compost to add good microbes to your soil: We compost (both in bins and worm compost – both work well). Hartin shared that 1 teaspoon of good garden soil with compost can add up to 100 million beneficial bacteria and 800 feet of fungal threads.
For more info:
-The Master Gardener programs in most states operate very helpful helplines to address public gardening and landscape questions. Use them!
-University of California home garden and consumer science publications website (searchable for composting, growing vegetables, etc.) or check in your state