Design trends

Where are the Dog Days of Summer?

What would summer be without sunflowers?

It’s been a cooler summer than the last few years. I’ve probably jinxed it now by mentioning that thereby insuring August will be a scorcher. But for now plants are happy they haven’t had to cope much with the “dreaded over-86-degree” weather when they can’t photosynthesize. It’s a good year also for those gorgeous dahlias and sunflowers, too. So will we have “The Dog Days of Summer” this year?

The Romans associated the weather from 20 days before to 20 days after the conjunction of the “Dog Star” with the hot days of summer. This falls between July 24th and August 24th. The name “Dog Star” comes from the ancient Egyptians who called Sirius, the Dog Star, after their god, Osiris. His head in pictograms resembles that of a dog. When the Dog Star rises in conjunction with the sun some felt the combination of the brightest luminary of the day, the sun, and and brightest star of the night – Sirius – was responsible for the extreme heat experienced during the middle of the summertime. Since Sirius is the brightest star in the night sky it’s reasonable to guess that it adds some heat to the earth but the amount is insignificant. We now know the heat of summer is a direct result of the earths tilt, but now you know… the rest of the story.

As summer rolls along you may become more aware of the different microclimates in your garden as some of your plants that used to get along just fine might be showing signs of stress. Taking note of these changes in the performance of your plants is what makes for a more successful landscape. When the weather cools towards the end of September you will want to move or eliminate those plants that aren’t thriving. Be sure to keep a thick layer of mulch on the soil around your plants to conserve that precious water you do allocate to each of your irrigation zones.

One thing I notice when I visit gardens for a consultation is the existing drip system has not been modified for many years, if ever, to allow for the growth of the plants. The emitters which were originally placed at the base of each plant are not even close to covering the current size of the root zone. The crown of the plant is getting overwatered with each cycle but the rest of the plant is bone dry. Time to add more emitters and move them away from the middle of the plant. No sense wasting water that’s not doing the plant much good.

The Dog Days of summer may be affecting our gardens but it doesn’t have to stop us from being out in the garden. The joy of gardening can take many forms including adding a wind chime, bird feeder or bird bath. Groom plants that need some cleanup. Many perennials benefit from a little haircut at this time of year to extend their blooming into the fall season. Santa Barbara daisies fall into this category. Lavenders will keep their compact shape by pruning a third of their branches now. This forces new growth in the center so the plant doesn’t get woody.

Deadhead flowering annuals and perennials as often as you can. Annuals like marigolds, petunias, zinnia and cosmos will stop blooming if you allow them to go to seed. The same is true of repeat blooming perennials like dahlia, scabiosa and lantana. These plants know they’re on this earth to reproduce. If they get a chance to set seed, the show’s over- they’ve raised their family. Try to remove fading flowers regularly and you’ll be amply rewarded.

Design trends

Plant Facts

All trees, including redwoods, communicate with each other.

My friend, Evan, often shares with me interesting studies about plants. Did you know that older trees share intelligence with young trees? Scientists have recorded how birch trees use electrical signals to communicate. How do they do this?

All living organisms have an electrical system. This study showed that the older trees, who had prior knowledge of an event like a solar eclipse, shared this knowledge hours ahead of time with younger trees. Because a tree relies on normal day-night cycles to transport nutrients and regulate water and reproduction, upsetting their internal clock, even briefly, can divert energy from defense chemical production which keeps pathogens and predators at bay. Sharing this information by the elders in the forest protects the young who may not have experienced such an event before.

What other fascinating things do plants do? I was very intrigued reading an article in Audubon magazine by Nathan Ehrlich. Scientists have discovered that plants give off electrical impulses in response to threats. Polygraph expert and former CIA interrogation specialist Cleve Backster confirmed this when, on an impulse, he hooked up a tropical dracaena to a polygraph and threatened the plant with a flame. The dracaena displayed the same electrical signals that people do when they lie. From lettuce to bananas, the results were similar.

Biologists Baldwin and Schultz published work suggesting that some plants can communicate through the air. When the researchers threatened poplars and maples they found that nearby trees, with no physical contact, released defensive chemicals that inhibit digestion, thus hindering predators’ ability to consume the trees leaves or bark.

Plants have many ways to defend themselves. One common way is by being poisonous or irritating. You can get severe eye burn if you get the toxic sap from a euphorbia in them. You just have to accidentally rub some sap near your eyes to trigger a reaction that will require a trip to Urgent Care. The pain can last for days and has been described as a very painful experience. Euphorbias are very deer resistant and drought tolerant and are being used more and more in gardens. Great plant that requires respect.

Many of us are growing milkweed (Asclepias) to attract monarch butterflies. The milky sap from this plant protects the monarch from being eaten and can cause the same painful burning of the eye. I read of a case where a gardener’s clothes brushed some stems while she was tending the garden. Later she wiped the sweat out of her eyes and didn’t realize she had also touched her pants. She ended up with cornea burn causing temporary blindness and had to take strong pain relievers and steroids to elevate the pain. Yikes.

Design trends

Good Groundcovers for a Changing World

Arctostaphylos uva-ursi ‘Radiant’ grows well in partial shade- even beneath trees.

Faced with what to use to keep down weeds when wood chips aren’t allowed? Well, you’re not alone. Although wood chip mulch is good for the health of your soil and your plants, it’s not recommended per new Cal Fire regulations within 30 feet of a structure. Recently I had a request from a client faced with just this dilemma. Here are some of the ground covers I recommended for her garden and for others in the past.

Living ground covers add beauty to the garden while holding the soil in place and preventing erosion. They contribute to soil health by encouraging microorganisms. A garden wouldn’t thrive as well without groundcovers.

Groundcovers are like a fancy carpet in the garden.They add richness and beauty under trees and become the stars of the show in sunny spots. Groundcovers reduce maintenance by preventing weeds and reduce watering by acting as a living mulch.

When choosing ground covers, assess the conditions of the area you want to plant.

  • Is it in the sun or shade?
  • Is it a naturally moist area or dry?
  • Do you intend to water it or go with our natural cycle of wet in the winter and dry in the summer?

Matching the plant to the site conditions will ensure success.

When designing a plant layout consider whether you want a sweep of the same plant or a tapestry effect with a variety of plants. Using more than one type of plant allows you to work with foliage contrast adding pattern to the composition.

Common Snowberry or Creeping Snowberry (Symphoricarpos) will hold the soil on steep banks. This native tolerates poor soil, lower light and general neglect. Evergreen Currant (ribes viburnifolium) and creeping mahonia also tolerate shady conditions. All the low growing ceanothus are great choices for sunnier spots as are the manzanita groundcovers. Smaller natives that put down deep roots are yarrow, coast aster, California fuchsia, wild grape, mimulus, buckwheat, wild rose and salvia including ‘Bees Bliss’.

Rubus pantalobus

Low water-use non-native groundcovers like cistus salviifolius, grevillea lanigera, rosemany prostratus, rubus pentalabous, correa and sarcococca are also good low-water choices.

Remember when setting plants on a steep slope to arrange them in staggered rows. Make an individual terrace for each plant and create a basin or low spot behind each one – not around the stem – to catch water. Set the crown of the plant high so it won’t become saturated and rot after watering or rain and make sure mulch does not build up around the stem.

To create stunning combinations of ground cover plants. choose 5 or 6 styles and repeat them in small drifts to carry the eye through the composition. Add grasses for linear texture. Good candidates are Blue Oat grass, a non-spreading clumping grass with silver leaves. Carex elate ‘Bowles Golden’ is a spectacular evergreen ornamental grass and Carex tumulicola (Foothill sedge) is another good choice for a grass-like plant.

There are many more choices for groundcovers that grow in the shade. Stay tuned.
Take the opportunity to survey your garden for bare spaces that can come alive with added texture and color.

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