Category Archives: irrigation

Make Every Drop Count:Best Watering Practices

Low water-use leucospermum or Pincushion.

Water is our most precious resource. One of the Apollo 11 astronauts recently said that the look back from the moon at our planet and blue oceans to be even more impressive than the moon itself. Life can?t exist without water. You are the steward of your own piece of planet earth. How you water can make it thrive and you can save water at the same time.

With summer water bills arriving this is a good time to re-visit how often and how much to water that landscape you?ve spent so much money to create. Basically, you?re wasting water if you water too shallow or too often. Here are some guidelines.

Photosynthesis is one of the most remarkable biochemical processes on earth and allows plants to use sunlight to make food from water and carbon dioxide. At temperatures about 104 degrees, however, the enzymes that carry out photosynthesis lose their shape and functionality. A garden that provides optimum light and water but gets too hot will be less vigorous.

California native Fremontodendron

Plants have natural systems that respond to heat problems. Plants can cool themselves by pumping water out through the leaves for a kind of swamp cooler effect. They can also make ?heat-shock? proteins which reduces problems from over heating. All these strategies can take resources away from a plant?s other needs like growth, flowering and fruiting.

So how much water do different types of plants need during the heat of summer?

Be sure that you water trees and shrubs deeply checking soil moisture first with a trowel. Established small to medium shrubs should be watered when the top 3-6″ is dry, large shrubs and trees when the top 6-12″ is dry.

As a rule of thumb, trees and large shrubs need deep but infrequent watering. They should be on a separate valve than your smaller shrubs and perennials. Water ornamental trees 1-3 times per month depending on the type and soil. Tree roots grow 12-36? deep and require 10 gallons of water per inch of trunk diameter.

Apply water with a soaker hose, drip system emitters or hand held hose with shut off and soft spray attachment according to your water district?s restrictions. Don?t dig holes in the ground in an effort to water deeply. This dries out roots even more. Be sure to water the root zone to the indicated root depth every time you water. Watering deeper than the root zone only means you are wasting water. You can test how deep you watered by pushing a thin, smooth rod into the ground soon after you irrigate. The soil probe should easily slide through the wet soil but become difficult to push when reaching dry soil.

The roots of smaller shrubs are 12-24? deep in the soil. Established native shrubs may need only monthly waterings to keep them looking their best while other shrubs may need watering every 7-10 days during the heat of the summer. Perennial roots only go down 12? or so and may need watering once or twice a week depending on type.

grevillea lanigera ‘Mt. Tamboritha’ groundcover

When is the best time to water? Watering in the morning is the most efficient whether you water by sprinkler, drip system, soaker hose or by hand. The water soaks deep in the soil without risk of evaporation. It bolsters the plant for the day and has dried from leaves by evening reducing the risk for foliar diseases like mildew. Plant roots are also more receptive to watering in the morning.

Is it true that water droplets will scorch leaves in the midday sun? According to a study, fuzzy-leaved plants hold water droplets above the leaf surface and act as a magnifying glass to the light beaming through them so there is a very slight chance of scorch. The study also reported that water droplets on smooth leaves, such as maples, cannot cause leaf burn, regardless of the time of day.

Lessons in Water Conservation

There?s a saying that you should learn something new everyday and while visiting Robby Franks? Scotts Valley garden recently I added valuable lessons to my irrigation know-how and successful succulent and other low water-use plant cultivation.

robby_frank_slope_sept2016_
Slope with dry creek bed, succulents and other low water-use plants.

You might remember a prior column of two about this ?serial mole killer? as Robby laughingly described himself several years ago. He told me he?s licked his huge mole problem by exclusion and trapping plus he?s been the benefactor of a large gopher snake and a couple king snakes from the neighbors so he?s pretty confident now that his garden and all the work that goes into dividing and transplanting and mulching will not go in vain.

The soil in Robby?s garden is quite sandy and thin. He?s done wonders adding his own compost over the years. We all know mulching is one of the best ways to conserve water in the landscape. Robby has long been an advocate of composting and regularly renews the mulch in his garden. He even calls himself “Mr Mulch”. He has permeable paths and a dry river bed that allow rainwater runoff to soak into the soil slowly. He keeps his plants pruned in a naturalistic manner because “smaller plants use less water'”. But all this wasn’t enough. His 3 “dumb timers”, as he calls them, were using too much water. That’s when he started researching weather based smart irrigation timers.

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The dry creek bed

“To me it seemed like an easy way to conserve water and it’s better for the plants as well”, Robby said. “It will increase the irrigation times if the weather is hotter and dryer than usual, decrease it if colder and turn itself off if it rains”. After research Robby eventually chose the Rainbird ?Simple to Set” Smart Indoor/Outdoor Irrigation timer.

At a raised feeding platform a covey of quail were enjoying an afternoon snack. Below a group of Mexican marigold, fortnight lily, society garlic and euphorbia were thriving and Robby explained they are all watered with one irrigation hub called an Apollo 8 Port Bubbler. It is simple to install and screws onto an existing sprinkler riser or other 5/8? tubing. Each port can be adjusted to deliver just the right amount of water to each area. Attached a micro spray to the end of the 1/4? tubing and plants grow larger and deeper root systems.

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Collection of plants requiring little irrigation

Robby?s garden is a diverse collection of plants from all over the world. He told me he?s been impressed how the cordyline are growing and considers them better performers than the popular New Zealand phormium in both heat and cold conditions. But succulents are his passion. He?s got five varieties of sedum, three types of aloe including his favorite ?Red Tip?, two varieties of sempervivum although he laments they are slower growing then he?d like, echeveria and his new favorite plant, Dyckia ?Red Devil?. Although technically not a succulent but in the genus bromeliad it does have similar characteristics. ?They remind me of an underwater scene?, he said. Their dark, spiky foliage did look a bit like giant sea anemone.

Robby does a lot a research and loves to share the knowledge he?s gained about plant cultivation and irrigation. Many a garden in Scotts Valley have benefited from his passion. Robby Frank is on a crusade to save water and Smart Irrigation and mulching is one way to do it.

Planting for Birds and Watering Tips

Purple-finch
Purple finch

My garden is alive with birds. Butterflies and bees also seem to find it an interesting place to visit. I?m always on the look out for plants that will attract even more of these exquisite creatures. Fortunately there are many that have low water requirements which is a prerequisite these days.

But how do you plant something new given the new water restrictions? And what about those existing trees, shrubs and perennials that birds, bees and butterflies depend on? How much water do they need to survive?

Everybody loves winged creatures in the garden. Adding plants that attract birds, bees and butterflies is at the top of the list of requests for nearly every garden that I design.

Trees that provide fruit, seeds, nectar and protein from insects attract many kinds of songbirds. Our native Big Leaf Maple is a favorite of the Evening Grosbeak who relish the seeds and early spring buds. Another bird magnet is the dogwood. Our Pacific dogwood as well as the Eastern dogwood and even the hybrid of the two, Eddie?s White Wonder, all are very valuable sources of food for many birds. Their summer berries are high in fat and important for migratory and wintering birds.

achillea_yellow
Achillea

In every garden possible I try to include low water use shrubs and perennials that attract birds. My favorite Lesser Goldfinch is partial to the seeds of yarrow, buckwheat and aster. Kevin?s mahonia is favored by Western bluebirds. Blooming now in our own neck of the woods is Mexican elderberry. Their butter yellow flowers will form purple berries rich in carbohydrates and protein and attract an incredible number of birds. And I always can find space for another variety of manzanita or ceanothus.

Both hummingbirds and butterflies are attracted to flowers that provide nectar. Among their favorites that won?t break your water budget are natives such as penstemon and salvia. Galvezia, mimulus, monardella, California fuchsia and ribes are also important nectar sources for them in your garden. Add a couple non-native, drought tolerant perennials like lavender, gaura, coreopsis, verbena, scabiosa, lantana and wallflower and you?ll provide a feast for all your winged visitors.

So how much water do different types of plants need during the heat of summer?

As a rule of thumb, trees and large shrubs need deep but infrequent waterings. They should be on a separate valve than your smaller shrubs and perennials. After the last two winters of little rain, many trees are showing signs of stress. It?s not easy to replace a tree that will take 20 years to regrow if you have to replant. Water ornamental trees 1-3 times per month depending on the type and soil. Tree roots are 12-36? deep and require 10 gallons of water per inch of trunk diameter.

Apply with a soaker hose, drip system emitters or hand held hose with shut off and soft spray attachment according to your water districts restrictions. Don?t dig holes in the ground in an effort to water deeply. This dries out roots even more. Be sure to water the root zone to the indicated root depth every time you water. Watering deeper than the root zone only means you are wasting water. You can test how deep you watered by pushing a smooth rod -1/4? – 3/8? in diameter- into the ground soon after you irrigate. The soil probe should easily slide through the wet soil but become difficult to push when reaching dry soil.

verbena_Homestead-purple
Homestead Purple verbena

The roots of smaller shrubs are 12-24? deep in the soil. Established native shrubs may need only monthly waterings to keep them looking their best while other shrubs may need watering every 7-10 days during the heat of the summer. Perennial roots only go down 12? or so and may need watering once or twice a week depending on it?s water needs.

With lots of mulch and the above watering tips you can keep all your plants happy and healthy for everyone to enjoy.