Category Archives: California Native Plants

California Native Plants, drought tolerant plants, mulching, water saving techniques, watering

Good Watering Practices

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philadelphus_Covered_BridgeThe recent heat wave was one for the record books. The temps were not the highest we've ever had around here but as each day melted into the next I kept thinking that fog, nature's air conditioning, was surely on it's way. Even drought tolerant plants need a little help at these times.

Watering is crucial as plants are growing vigorously. Water makes up 90-98% of every plant we grow. It's needed for photosynthesis, as well as reproduction and defense against pests. Checking soil moisture and improving a soils ability to absorb and hold water should be a priority when you're out in the garden. Don't wait for plants to wilt and burn before correcting watering problems.  

There are ways to water more efficiently and ways to conserve that water. Now is the a good time to review some good watering practices and guidelines.

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 sun? According to a study published in New Phytologist, a journal of research in plant science, there is a slight risk of leaf burn on fuzzy leaved plants in the sun. The hairs can hold the water droplets above the leaf surface and act as a magnifying glass to the light beaming through them. The study also reported that water droplets on smooth leaves, such as maples, cannot cause leaf burn, regardless of the time of day.

I my forty years of gardening, my own observation is that the leaf burn on a fuzzy leaf must be very small, indeed, as I've never observed any damage. If you find a plant needs water midday, by all means go ahead and water it. Containers even benefit from the cooling effect that watering provides

Most plants need 18" depth of well-drained soil to thrive although trees and many vegetables roots grow several feet deep. More than an inch of water per week may be needed for their success and in the case of many trees and native plants, deeper but more infrequent watering is required.

You can easily measure how much water you are applying. If you have a sprinkler system, place a straight-sided container like a tuna can on the outside edge of the area being watered. Let the sprinkler run until one inch of water has accumulated in the can. When using a drip system or soaker hose, irrigate until a 3" deep test hole dug 1 ft out from the emitter or end of the soaker is moist. Moisture at that level indicates than an inch of water has been applied. The best way to determine how many inches of water your soil needs for a good soak is by digging down after the water has had a chance to settle. When watered well, the soil should feel cool and damp at the bottom of the hole. If the soil feels warm and dry you haven't watered long enough. You need to do this test just once to get a feeling for how much water your soil can hold and how deeply it's soaking in.

if you have a lawn, decide if you really need it that large and maybe not in the front yard at all.  Keep the mowing height high during the heat of summer.  Mow when the grass is about a third taller than recommended height. For common fescue, mow when the grass is 3-4" tall, with your mower set at 2-3 ".  Fertilize only when your lawn needs it to keep a good green color.  Over fertilizing results in quick top growth which needs more water and is susceptible to insect damage and fungus problems.  A good rule of thumb for watering a lawn is to water 1 x per week when the temperature is 70 – 80 degrees., 2 x per week when it's 80 – 90 and 3 x per week only when it's above 90 degrees.  Make sure the water soaks in encouraging the roots to extend  30" below the surface which will make your lawn more drought tolerant.
 
Consider replacing your lawn with a walk-on ground cover like woolly thyme or chamomile.  You can't play touch football on these ground covers but they will tolerate light foot traffic.  Another alternative is to plant low growing native grasses that require only a handfull of trims per year compared to a conventional lawn.
 
Water wisely in other areas of your garden.,  Construct soil basins and furrows to direct water to plant roots and increase this basin as the plant grows or use a soaker hose on the surface to slowly water at the drip line of trees and shrubs. Fruit trees, citrus and flowering trees need a deep irrigation every other week. Less thirsty established trees like Chinese pistache and strawberry tree need irrigation about once a month. Newly planted trees need water regularly. Gradually reduce frequency after a year or so.

And above all, mulch, mulch, mulch.  Cover the soil with at least 2" of organic mulch such as compost or chipped bark.  The mulch holds in moisture as well as keeping roots cool and gradually decomposes and enriches your soil.  Keep it away from the base of trunks or plant stems. Don't use rocks or gravel as a mulch because they add heat to the soil and moisture evaporates faster.

Take good care of your plants this summer.
 

California Native Plants, groundcovers, invasive plants, organic weed contol, organic weed control, shade plants

What to Do about Invasive Plants

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bull_thistleWe can't control those pesky weed seeds that blow into our gardens and take hold. There are ways to keep them from taking over, however. But what about those invasive plants that are already in our gardens like ivy and vinca major? What's the best way to deal with them? Then there are plants we buy ourselves that can invade natural areas. Are there better plants to use that are just as attractive and useful? Here are some solutions to make your garden happy.

One invasive thug that can take over is bull thistle, a relative of the edible artichoke. The seeds of this vigorous exotic take hold in disturbed areas including your beautiful garden soil and if not controlled can become a solid mass of impenetrable thistles in just a few seasons. Bull thistle only reproduces by seed so removal of the flowering stalks at this time of year will prevent them from spreading. The flowering heads must be discarded in a plastic bag and destroyed to keep them from forming viable seed. Because this weed is biennial you also need to dig out the first year plants that have not formed stalks. You can also mow thistles close to the ground a couple of times before they form stalks to reduce the population over time.

As a landscape designer and consultant I'm often called upon for advice for an area covered with vinca major or ivy. Both of these invasive species are too successful for their own good, smothering native plants and harboring pests such as rats and snails. Vinca major also serves as a host to the bacteria that causes Pierce's disease in grapevines. For your information, vinca minor has not been found to be invasive in California so far

You can choose organic methods to control vinca and ivy rather than chemical herbicides. Hand vinca_majorremoval is labor intensive but the results are good if all the root nodes and stolons are removed. Work inward from the perimeter of the patch and pull the plants back. You will need to do this every 3 months during the first year to remove resprouts but native plants may recolonize the area and reduce the chance that other weeds will move into the area following the disturbance caused by the removal activities.

Replanting with another more desirable groundcover is another solution. For shady areas, try planting wild ginger  (Asarum caudatum), Catalina perfume ( Ribes viburnifolium), creeping snowberry ( Symphoricarpos mollis), yerba buena ( Satureja douglasii ), bear's foot hellebore (Helleborus foetidus), winter saxifrage (Bergenia cordifolia), pachysandra, Serbian bellflower (Campanula poscharskyana) or Asian jasmine.

Good substitutes for vinca or ivy in sunnier spots include groundcover types of manzanita and ceanothus. Also attractive are Taiwan raspberry (Rubus pentalobus), California fuchsia (Zauschneria), or beach strawberry (Fragraria chiloensis ).

Some plants even though purchased from a nursery can cause problems. You wouldn't buy a Scotch or French broom knowing how invasive they can be. Forsythia, Japanese kerria, golden currant and Jerusalem sage all provide that beautiful spring butter yellow color in the garden.

The licorice plant (Helichrysum petiolare) gained popularity for its deer resistance and foliage color many years ago. Unfortunately, it self sows wildly and the spreading branches will root at any point of contact with the ground. Try instead better behaved plants like California natives salvia leucophylla or eriogonum giganteum. Teucrium germander or Powis Castle artemisia also work well in the same area.

Another good plant gone wrong is cotonester  lacteus (parneyi).  The red fall berries are spread by cotoneaster_lacteus_Parneyibirds and with their rapid growth and competitive roots they can overtake the garden and wild areas. Fortunately there are many other plants to use instead that provide food for birds and are beautiful, too. Try planting toyon (Heteromeles arbutifolia) a California native with delicate white flowers and large clusters of brilliant red berries. Pineapple guava is another good substitute as is strawberry tree (Arbutus unedo).

These are just some of the suggested alternatives for invasive garden plants for this area. Don't give an invasive an inch, it can take over your garden, the neighbors and our wildlands.
 

California Native Plants, Deer Resistant Plants, flowering shrubs, flowers, wildlife gardening

Spring Flowering Shrubs

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In the spring we are surrounded by flowers of every color. It's our reward after the winter. My heart goes out to those gardeners in other parts of the country where snow still covers their perennial beds. The availability of winter sports only goes so far as consolation for all that white stuff. I've lived along the coasts of California my whole life and personally, I'd rather be sitting out in my garden enjoying the birds gathering nesting material than planning the summer garden on paper.  But I digress. Early spring flowering shrubs are getting my attention these days and here are a couple of varieties that you'll want in your garden, too.

ceanothus_Celestial_Blue 2There's a ceanothus for every garden. You can't have too many of these workhorses in the landscape. They range from groundcover types for erosion control to shrubs for screens and accents. A new variety I've recently learned about from my friend and fellow Press Banner columnist, Colly Gruczelak, is called Celestial Blue. She planted several 2 years ago from 4" mail order sleeves and now they are 3 ft tall and 4 ft wide. In her sandy garden, home to her personal deer population, the flowers look like blueberry sherbet.

With a light fragrance, described as grape tart, this medium shrub makes a good screen or accent. This cultivar is probably a hybrid of Julia Phelps and Concha. A horticultural cultivar is simply a plant variety that's been selected specifically for gardens.  Celestial Blue flowers 9 months a year especially in the summer when it explodes with rich purplish blue flowers.

Ceanothus provide excellent habitat for birds and insects. They are good for attracting bee and fly pollinators and are the larval host plants for the beautiful Ceanothus Silkmoth. Ceanothus seed is readily eaten by many local birds. Even a deer resistant plant like ceanothus may have its new tasty growth tip-pruned in spring and summer. Think of this as natures way of producing a well shaped shrub, dense and compact.

Planting a ceanothus is an important step to attracting more birds and wildlife to your garden.
rhododendron_occidentale 2
Want even more fragrance in your early spring garden? Plant a Western azalea, the common name for rhododendron occidentale. One of our most beautiful native shrubs in the Coast Ranges it grows also on the western side of the Cascades and Sierra Nevada mountains.

Western azaleas were described by explorers in western North America in the 1800's. The plant contributed to the development of deciduous hybrid azaleas in Great Britain such as the Exbury azalea.

If you're out hiking you'll know you are near a stand of these awesome shrubs by the sweet and spicy clove scent reminiscent of cottage pinks and carnations. Western azaleas are tolerant of our native serpentine soils which are high in iron and magnesium. Like many of our western shrubs, they have the capacity to resprout from the ground if the top has been destroyed by fire as long as the root system remains intact.

To grow Western azaleas in the garden provide routine moisture and keep the roots cool by shading the root zone with a deep mulch. Protect them from hot afternoon sun. Also to prevent late summer mildew provide air circulation by growing them in open areas not crowded among understory plantings or in dead air spaces under eves.

Give this lovely native shrub aloropetalum_chinense 2 try. It's a wonderful addition to your garden. Visit some of them in Henry Cowell and Big Basin to see them first hand this spring.

My other favorite early spring blooming shrubs are Lily-of-the-Valley shrubs. I especially like a two-tone dark rose variety called Dorothy Wyckoff although those with pure white flowers are spectacular in the garden, too.
The white flowers of loropetalum chinense or Fringe Flower are even more showy than its pink flowering relatives.
Add a graceful, double butter yellow flowering kerria japonica to your landscape, too. Your spring garden will be a rainbow of color.