To have a garden at all is a privilege. We use precious resources to create nurturing and beautiful gardens. Our most valuable resource is our time. Just as in our lives outside the garden we need to prioritize how we use our available time for the garden. We need to understand the process we are involved with, and why we are doing it. How we experience our gardens is everything. If your garden is a burden, you feel guilty and avert your eyes, and you are using water without a strategy you are destined to lose interest and thus lose control.
What does this have to do with water? We live in a time of increasing demand, cost , and decreasing water supply and unpredictable weather patterns. Rather than starting with a list of water saving techniques I prefer to start with a discussion of the effect of water in your garden context.
Watch your garden closely and it will tell you clearly what is going on. In the greater Bay Area for example we live in a regional context of a Mediterranean climate. This is defined as a mild wet winter followed by a long dry season. Within this context we have a myriad of microclimates that dramatically affect your garden. These vary from coastal, interior valleys, foothills, mountains and desert to name a few. Add to that the microcosm of your site, structures, existing trees, and slope aspect and degree of shade and you can see the danger of over simplification.
A garden ecology is another creature all together. We assemble plants from all over the world. Ideally we group them together in compatible plantings, which have similar water needs. But we do not really know the natural context of what we plant. Typically we are relying on the garden tolerance of plants rather than their provenance or hybrids developed for increased garden tolerance, frost resistance, and flower size etc.
You can tell a lot about a plant by how it has adapted to water loss. Nature is a harsh mistress. Plants have adapted with a variety of techniques to reduce water loss. This starts with waxy leaves or resinous sap, includes the reduction of the size of the leaf or to the extreme of no leaves at all. Blue and Silver foliages reduce water loss. Bulbs and annuals are the most advanced in this aspect. They close up shop in the dry season. With annuals this can mean lying dormant for multiple seasons until conditions are just right.
Plants also adapt to their seasonal variation and rainfall in how they time their flushes of growth. Plants are most susceptible to drought as their new growth pushes out. I am sure you have noticed this in your own garden, as the first part of the plant to flag or wilt is youngest growth. When the plant has hardened off later in the season it is the older foliage, which turns yellow and begins to drop. One needs to recognize the first signs of water stress with plants. This can include a dulling of the color of the foliage with curling at the edges. Water pressure in the plant is critical to the structure as well, thus the entire plant will begin to droop.
When we push growth out of season with heavy fertilization and regular summer watering we increase the pulse of the garden. This is particularly true of summer dormant plants such as many of our Mediterranean plantings. Lavender and Rockrose are good examples of plantings, which become short lived as a result. We need to summer prune to reduce foliage and counter this effect. If you get seven years with Lavender with regular pruning you have done well.
With woody plants where we put the water is an issue as much as the amount of water. Older trees such as Blue Oaks (Quercus douglasiana), and Live Oaks (Quercus agrifolia), are very susceptible to crown and bark infestations when regularly wetted by irrigation. A good rule of thumb is to leave the soil dry as possible within three to four feet of the trunk of older trees.
Trees that grow in areas of high water table have their feet in the water. Thus irrigation is not as much as an issue with them as long as the trunk base is kept dry.
In our Mediterranean climate water creates maintenance thus its application and timing is everything. I even water Native Oaks during the winter in a dry winter year. I seek to make every year a ‘good’ year in the garden.
What is your vision of your garden? If it derives from an Arcadian vision of lush green meadows artfully framed by trees you will by definition be using a great deal of water. The passage of seasons in gardens should be celebrated and not denied by trying to make the garden look lush and verdant in August. You have only to look at the iconic view of the California landscape to see a different aesthetic at work.
In a smaller or contained garden this is not as much an option. But I am of the opinion that most gardens are over-watered. It has been my experience in evaluating existing gardens that they as often suffer from over-watering as lack of water.
This is usually due to a false sense of security created by our automated gardens. Who controls the irrigation controller? We are either intimidated by it and tend to avoid reprogramming it or we delegate it to a gardener of ‘Mow and Blow’ qualifications. What is wrong with this picture?
Irrigation technology has improved dramatically in the last twenty years. In older gardens with historic and corroded piping, leakage, inefficient irrigation heads, and outdated irrigation controllers are working against all your best efforts to save water. Usually it is better to start again with a new system than to continue the accretion addition of new generations of irrigation equipment onto older infrastructure. Most of my gardens are a combination of drip, xero flow and overhead irrigation.
The cost of local weather stations or water sensors tied to your controller have come down in cost to a range that makes it cost efficient for larger gardens. However, I am still suspicious of leaving the handing of your water use to the intelligent water computer. Ultimately someone has to look closely at the garden at frequent intervals every two or three days.
Learn to accept seasonal variation and to a degree drought dormancy. I used to take care of the California Native Collections at the US Botanic Garden and found that you could water in the summer without generating growth while keeping a healthy and vibrant plant. Manzanita’s will drop foliage and lose their rich foliage color in damaging drought. The same plant will keep all its foliage and look great with one or two watering in a long dry season.
It comes back to environmental literacy. If you understand the dynamics of plant growth, and watch closely, you will save tremendous amounts of water and be more efficient with your time and garden.
Practical Suggestions for Saving Water in Your Garden
1. Create a garden, which reflect your available resources of time and water.
2. Prioritize your horticulture. Create garden areas with the highest pulse or growth dynamic in areas you will interact with most closely. Gardens are not only drought tolerant or water demanding. They can be a well-designed mixture of water demands that reflects your interaction with them.
3. In peripheral garden areas avoid complex layered plantings. Natural woodland duft and beautiful trees can be sufficient.
4. Plant seasonally. Do not expand your garden or infill with planting in August if you can help it. New plantings tend to be in nursery soils, which are very light, and when inter-planted with existing garden plantings require additional water to establish. Thus you tend to overwater the entire garden for the benefit of the few.
5. Reduce soil compaction by forking or aerating the soil. This increases water percolation and reduces water wastage.
6. Mulch. This is the best thing to do in the garden with the most dramatic improvement for water conservation. Mulching not only conserves water but reduces compaction, cools soil temperatures in the summer, and adds to the soil fertility when organic. This also reduces weed growth and can give a presentation finish to the garden.
The important thing here is not to bury the crown the plant. This can be avoided if the plant is planted slightly higher and then mulched immediately after planting. With a one-gallon plant it may be as little as an inch. Do not over plant in holes with a lot of imported soil under the plant as you get a lot of subsidence over time. This in combination with summer water will rot the crown.
Mulches can also be rock or crushed stone. If you are using rock mulch remember to prepare the soil to fork in organic material before the mulch, as stone will not contribute anything beyond reducing weed growth, soil temperature, and water loss.
7. Healthy well-proportioned root systems will create stronger plants thus be more drought tolerant. Wet the root evenly. When using drip use more emitters, inline emitters or stream flow emitters to more evenly distribute the water. It is important with larger plants with rootballs that the emitters be on top of the rootball initially or the water can bypass the plant before it has a chance to put out new roots. I recommend using soil penetrants on new specimen rootballs to initially thoroughly wet the plant’s root area.
8. If you raise the organic matter in the soil you will find that the soil will turn itself. More accurately the worms in the soil will turn it for you. I like to use worm-casting compost mixed in with a fine aged arbor mulch. A friable soil will retain much more water and create a vibrant garden.
9. Make your irrigation efficient, evaluate your irrigation system carefully and upgrade.
10. Set your irrigation clock for slightly less water than you think is necessary and give extra cycles as required.
11. Add irrigation valves for added control. This allows you to water your landscape according to its relative value. For example I always separately irrigate my trees from the rest of the garden. This guarantees good establishment. I later phase out this valve.
In some of my drought tolerant gardens I have used roses, which are surprisingly tough. I put them on their own valve so I can give them more water without affecting shrubs near by. This is done with drip. With the extra water the flowering time is extended and the quality of the flowers improved.
With important screening you can put it on its own valve. Often these plants are not given much attention since they are on the perimeter where it is easy to forget them. Yet they may have a critical function relative to your enjoyment of your garden.
12. Review the extent of your lawns. Since the lawn is the single most voracious user of water in your garden you want to start by questioning your square footage of lawn. Lawns are great to have. They simplify and present the view; they provide recreation, entertainment areas while keeping terraces to a minimum. Lawns, which are there because that was the simplest solution, or to conform to the neighborhood will need to be rethought. Managed meadows, verges, low bunch grasses, and prostrate groundcovers and just duft or mulch can all be in the mix as alternatives to classic turf.
13. As long as you are standing there have a hose in your hand. To accomplish this you need to have hose bibs readily accessible. I regularly hand water those plants, which benefit with just a bit extra water. Lets face it we all break the rules as to the compatible planting regimes. It is also important to wash the foliage in areas on drip irrigation, as the dust build up can be considerable in late summer.
This can also be done with manually set sprinklers. The important thing with these is that they are used in conjunction with an automatic manual timer set on the hose bib. We inevitably leave sprinklers on and forget about them defeating the purpose of saving water, which was our aim to begin with.
Problems that are spotted early can be dealt with before damage is done. Similarly you will also make exciting discoveries in your garden otherwise easily missed by looking frequently at your garden. Remember that a garden is an evolving illusion and unstable ecology and not something static to be “Maintained”.
14. Focus your efforts and understand your limitations and resources. It is better to do an area well than everything poorly.
If you do all of the above you significantly reduce your water use 30-40%, you would get to know your garden far better, and you would become environmentally literate. Someone who sees the environment and understands the dynamics of plant growth, will be able to be more effective in striking a balance between garden perfection, change, and illusion.
