Design trends

Fourth of July in the Garden

A local black-tailed deer celebrating Fourth of July

I don’t grow corn in my small, shady garden so I’m not sure how tall they’d be if by now if I planted on May Day when the soil was 50 degrees, but that’s how the saying goes. This column isn’t about growing corn, however, it’s about climate smart plants that hold up to the heat. So let’s get started.

All this talk about “drought tolerant” plants or “water smart” plants is misleading in some ways. What really matters for the success of a plant in your garden is that they are climate smart. You can call the new California garden climate tolerant or climate adapted but it all comes down to the same thing. The plants you choose to grow in your garden should be able to naturally tolerate periods of lower than average water. This doesn’t mean no water during extremely long dry periods. No plant can live without water.

All of us live in a summer-dry climate. Summer-dry gardens are naturally dry for long periods. Knowing which type of plant community you live in can make the difference between success and failure in your garden. Choose the right plant for the right place whether it’s a California native from an area with similar soil and exposure or a plant from another Mediterranean-like climate with growing conditions like yours.

Plant communities have evolved over time with geologic changes in climate, topography and soils. We have several district areas here- mixed evergreen forest, redwood forest, chaparral and sandhills.

If you live in a mixed evergreen forest you garden with trees like coast live oak, tan oak, madrone, bay and buckeye. Understory plants include ceanothus, coffeeberry, hazel and poison oak. Your soil contains serpentine and granite. Many other unthirsty plants like salvias, lavender, santolina, society garlic, giant feather grass, rosemary and rockrose do well here. California natives such as western mock orange (philadelphus lewisii), wild ginger and western sword ferns grow here also.

Mixed evergreen forest may also be found along canyon bottoms near streams where big leaf maple, white alder, cottonwood, and western sycamore trees grow. Most plant here grow lush in this deep soil. If you are looking to add something new to your garden here consider giant chain fern, aquilegia, dicentra, Pacific Coast iris and fuchsia-flowering gooseberry.

Chaparral areas are the hottest, driest slopes of these mountains. Dense thickets of manzanita, coyote brush, chamise, coffeeberry, ceanothus, monkey flower and sage are native here. These plants are adapted to little water and often have tiny, thick, waxy, light green or grayish leaves. Soils tend to be rocky and shallow with overlaying rock or a subsoil that is mostly clay. Plants here need to have an extensive root system that reaches widely and deeply for water. If you live here a classic combination would be the spring blooming western redbud and Julia Phelps or Dark Star ceanothus. The combination of magenta and electric blue flowers is unforgettable.

The sandhills near Quail Hollow and Bonny Doon around Martin Rd. are part of an ancient sandy sea floor that was uplifted, eroded and exposed. These sandy soils lack organic matter and nutrients and their white color magnifies the temperature of the summer sun. Unique, native plants like silverleaf manzanita and Ben Lomond wallflower live here. Buckwheat and sticky monkey flower do well here. You might also try growing Siskiyou Lewisia, a pretty little plant native to northern California, thrives in sand and gravel soils with good drainage. This 8″ tall hardy perennial blooms from spring to early summer with extremely showy flower clusters in colors ranging from apricot to pink, rose and bright cherry red. Mulch them with gravel or crushed stone.

Remember: right plant-right place. Don’t try to force nature although most gardens do look better with some summer water. Closer to the house we expect a fuller look. Combinations I’m going to try this season include leucospermum paired with blue echium or grey-leafed westringia planted with red-flowering callistemon ‘Little John’.

Design trends

Watering the Right Way

Salvia Hot Lips is popular in drought tolerant gardens.

Think like a plant. The weather might be cool one day, really hot the next day. And your plants are growing like mad in order to reproduce which is their s life’s work. All this takes water which is the elixir of life for us and all living organisms. But just how much water do my plants need? I don’t want to overwater and waste this precious resource but neither do I want to lose my botanical friends. Here are some guidelines you might find helpful.

All plants need water- even those that are tolerant of our summer-dry conditions. Water makes up 90-98% of every plant we grow. It’s needed for photosynthesis, as well as reproduction and defense against pests.

With summer water bills arriving soon 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’re not watering deep enough to moisten the entire root ball or if you’re irrigating too often.

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 above 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.

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 inches of soil is dry. Water large shrubs and trees when the top 6-12 inches 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 inches 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 recommendations. 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 reach 12-24 inches deep in the soil. Established native shrubs may need only monthly watering 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 inches or so and may need watering once or twice a week depending on type and weather.

When is the best time to water? Watering in the morning is the most efficient time whether you water by sprinkler, drip system, soaker hose or by hand because the water soaks deep in the soil without risk of evaporation. This 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. Don’t forget your pots. On a hot day, you can water midday to not only supply moisture but to cool the soil. You would’t want to live in a pot where the temperature at the roots could reach over a hundred either.

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. But no matter the time of day, a plant that needs water should get the right amount. In all the time I worked at a nursery I never saw a plant that was scorched by water on the leaf surface no matter what time of day it was watered.

It’s no surprise that many California natives are adapted to high temperatures. Some California native plants that can handle the heat with little water include salvia, mimulus, California fuchsia, eriogonum, manzanita, artemisia, California milkweed, ceanothus, mountain mahogany, bush poppy, bush lupine, native penstemon, monardella, mahonia nevinii, fremontodendron and holly-leafed cherry.

Other well adapted plants that are known to be more tolerant of heat include butterfly bush, germander, rosemary, smoke tree, rudbeckia, coreopsis, lantana, plumbago, gaillardia, lilac, sedums, oregano and verbena.

Design trends

Year-Round Bouquets

Want to be able to walk outside and pick some flowers to take to a friend’s house or bring inside to enjoy yourself? Not long ago I was looking around my own little garden for good flowers to cut for a bouquet. I had some snapdragons, hellebores and lily-of-the valley shrub flowers to cut. Now I’m thinking about what flowers will be blooming soon and what I might plant now to add to my garden.

Besides snapdragons that bloom almost year round and were recognized as ’Cut Flower of the Year” by the Association of…Cut Flower Growers, I have Crocosmia that will be blooming soon. Their arching stems and brightly colored, long-lasting blossoms will look great in a bouquet.

I also have old fashioned Shasta Daisy. Those long sturdy stems hold up well in a vase. Growing also in my little garden are Calla lily, Alstroemeria, Hydrangeas and Roses. Unfortunately my Flowering Maple (abutilon) which the hummers love, have a very short vase life is.

Until about 100 years ago, one of the most important areas of any large garden was the cutting garden where flowers were harvested like a crop and taken inside for display. Today our lifestyles and tastes are reflected in bouquets that are more casual. The bouquets you make from garden grown flowers, interesting foliage branches, grasses, vines and even herbs always seem to have more personality and cottage garden softness than ones bought from the store.

Flowers that lend themselves to cutting with long stems and a long vase life can be incorporated into any spot of the garden but if you enjoy lots of cut flowers indoors you may want to sett aside a small bed primarily for an old-fashioned cutting garden. A seldom used side yard would be an ideal place as long as it receives at least a half day of sun. Or how about that narrow bed along the fence you never know what to do with? if you’ve never planted in the soil of your future cutting garden, amend the soil generously with organic matter or compost. Then water to germinate weed seeds and hoe them off. Don’t turn the soil again as you’ll bring up more weed seeds. Now you’re ready to plant.

In shady gardens, fragrant daphne odora is a wonderful small shrub that provides interesting variegated foliage as well as flowers. Sweet olive or osmanthus fragrans blooms smell like apricots. Oakleaf hydrangea foliage and flowers look great in bouquets and the leaves turn red in fall which is an added bonus. Our native shrub philadelphus, also called mock orange, has flowers that smell like oranges and will grow in some shade as well as sun. Pittosporum ‘Marjorie Channon’ will add white with a hint of lime to your bouquets.

For sunny spots grow perennials like penstemon and kangaroo paw. Also coneflowers, dahlias, gloriosa daisy, delphinium, foxglove, scabiosa, aster, shasta daisy and yarrow are good as cut flowers. Coreopsis attract butterflies and are long lasting in bouquets.

Self-sowing annuals that have a long vase life are bachelor buttons, clarkia, cosmos, flax, love-in-a-mist, nasturtium, cleome and calendula. Annual flowers such as zinnia, lisianthus, snapdragon, statice and marigolds are great in containers where you can make every drop of water count and are also good for cutting.

Native flowers that last for a week or more include Clarkia and Sticky Monkeyflower. Yarrow and hummingbird sage will last 4-6 days.

While just about any plant material that strikes your fancy will work in a mixed bouquet there are four types of plant forms that naturally look good together: Spires for height and architectural properties with flowers like liatris, snapdragon, gladiola, salvia, Bells-of-Ireland as well as the strappy leaves of flax or cordyline. Round flowers such as roses, dahlias, long-stemmed marigolds and peonies provide focus. Lacy flowers are fillers- ferns, baby’s breath, dill. Foliage from shrubs such as abelia, breath of heaven, California. bay, ornamental grasses, grapes and other vines, herbs, woody tree branches like smoke tree and Japanese maple which also look handsome in a bouquet.

A deconstructed arrangement separates each type of flower into their own vase or container instead of grouping them in a mixed bouquet. Vary the size and shape of the vases and containers and group them together to create a unique vignette.

The Mountain Gardener's Weblog