The Dog Days of Summer

Swallowtail butterfly- a regular summertime visitor.

They’re called the Dog Days of summer. You know, those sultry days with the hottest summer temperatures. 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.

The Romans associated the hot weather from 20 days before to 20 days after the conjunction “the dog days of summer” because it coincidentally fell at the time of year when it was very hot. This falls between July 24th and August 24th. The Old Farmer’s Almanac uses slightly different dates but the Dog Days of summer are definitely here.

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. With the drier and hotter weather this year, 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.

Add the soothing sound of wind chimes to your summer garden.

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.

Swallowtail butterflies are regular visitors to the garden at this time of year. They especially like butterfly bush as well as zinnias and many other flowers. They are easy to photograph if you move slowly.

How Plants Survive in the Heat

Growing back after the fire this California fuchsia is hoping to attract hummingbirds, bees and butterflies.

What happens to a plant when the thermometer tops 100 degrees ? Planning for more hot weather this summer is a requirement for a successful garden. Are there some plants that can survive tough times more easily?

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. But at temperatures about 104 degrees 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. Tomatoes, for example, will drop blossoms and not set fruit if temperatures are over 90 degrees. Plants that endure high heat can be stunted, weakened and attract pests and diseases even if water is available.

Plants do have natural systems that respond to heat problems. Some plants are better at this than others. 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 do take resources away from a plants other needs like growth, flowering and fruiting.

It’s no surprise that many California natives are adapted to high temperatures. Walking my old property the other day I noted which plants are regrowing after the fire, despite little winter rainfall. Every plant burned to the ground. The climate is much hotter up in Bonny Doon now that the tree cover is gone. The redwoods are trying to regrow but it’ll be decades before they provide shade again. Those plants that have regrown the best include California fuchsia (epilobium canum). They spread by underground rhizomes so it’s not surprising they survived. I didn’t see any bees or hummingbirds around but one of these years they’ll return. Another survivor is hummingbird sage (salvia spathacea). They are just starting to regrow and were not in bloom.

The Bees Bliss Sage, a low groundcover that can reach 6-8 ft wide is another plant that I used to enjoy. It has an extended bloom time from mid-spring to early fall with whorls of lavender-blue flower spikes. Bees, butterflies and hummingbirds all find it attractive. The jury’s out whether it’ll return or not.

Another plant that can handle high temps is salvia clevelandii. Their blooming cycle of electric blue-purple flowers will last through the summer. This salvia survives without any supplemental irrigation but if you give it an occasional deep watering and wash off the foliage every so often it’s much happier.

Who doesn’t like color in their garden? Mimulus or Sticky Monkey Flower blooms are showy and the hummingbirds love them. The Jelly Bean series has added bright pink colors in addition to white, orange, red and yellow but the traditional aurantiacus types are the most tolerant of drought.

Other California native plants that can handle the heat with little water include eriogonum, manzanita, artemisia, California milkweed, ceanothus, mountain mahogany, bush poppy, bush lupine, native penstemon, monardella, mahonia nevinii , fremontodendron and holly-leafed cherry.

Non-native 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.

This New Zealand tree fern although not a native is growing back after the fire with no water. Nature is resilient. I thought it deserved some recognition.

These plants can be the rock stars of your garden. Some natives that are able to survive with no irrigation after 2 years may look more attractive with a few deep waterings per summer. And don’t forget the wood chip mulch to encourage the soil microbes and keep the soil cool.

Fun Facts from the Garden

Bob, the hosta seboldiana in bloom.

I confess, I’m not one who talks to plants. Although I have a huge hosta seboldiana named Bob as well as an offset that I cleverly named Bob the Second, I don’t address them personally. Maybe that’s going to change. I was very intrigued reading a recent 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 have 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.

One of my favorite classes when I attended Cal Poly San Luis Obispo was Plant Taxonomy. On the surface the subject sounds a little dry but the professor was all about plant reproduction which is quite exciting and more varied than you think.

It’s fascinating to mark time with events in the botanic world. There’s even a word for it- Phenology. Websites like USA National Phenology Network offer lots of information on the subject. Visit

Phenology is the study of plant and animal life cycle events and how these are influenced by seasonal variations in climate. When do they occur each year? Phenology is a real science that has many applications. In farming and gardening, phenology is used chiefly for planting times and pest control. Certain plants give a cue, by blooming or leafing out, that it’s time for certain activities, such as sowing particular crops or insect emergence and pest control. Often the common denominator is the temperature.

Indicator plants are often used to look for a particular pest and manage it in its most vulnerable stages. They can also be used to time the planting of vegetables, apply fertilizer, prune and so on. Record your own observations to start a data base for our Another great site is National Sustainable Agriculture Information Service at Sites like these can also help you design orchards for pollination and ripening sequence, design for bee forage plantings, design perennial flower beds and wildflower plantings as well as plantings to attract beneficial insects and enhance natural biological control. How cool is that?

But back to plant reproduction. Mosses reproduce from male and female mosses which produce spores. Conifers produce two type of cones on the same tree. Wind blows the pollen to another cone which combine to make a baby conifer which lives in a seed inside the cone.

Flowering plants like this Princess Flower have both male and female parts in each flower.

Then there are to most advanced plants – the flowering plants. Some flowering plants have both male and female flowers. They are monoecious meaning “single house”. Dioecious plants have male flowers on one plant and female flowers on another. Plants that rely on flowers for reproduction are very dependent on outside help such as insects and animals which is where we come in. Be a citizen scientist in your own backyard.

Celebrating 800 Columns

The author in her old garden in Bonny Doon before the fire.

Since writing my first column in October 2005 I have shared with you, my good readers, many a gardening tip, confession, aspiration, resolution, success story and utter failure in my garden. We live and learn from our mistakes. We gardeners love to swap stories and sometimes I learn as much from you as you do from me.
We gardeners are eternal optimists. Why else would we plant a tree, a seed or a garden?

With Guatemala and Honduras in the news I recall my trip there in 2007. On Utila, an island off the coast of Honduras, I noticed plants growing in washing machine baskets. I thought it was a clever way to re-use old appliances but wondered why there were so many old washing machines on a tiny island. A local laughed and told me the baskets protect their plants from the big blue crabs that come out at night. Seems the crabs will sever the stem right at ground level and drag the whole plant into their hole. Also the baskets protect the plants from the iguanas who will eat anything within two feet of the ground. And you thought deer, gophers and rabbits were a problem?

Sherman is caught red-handed licking the buttermilk/moss mixture from the wall.

I lost my dog Sherman recently but one of my favorite anecdotes about him involved a wall and some buttermilk. The interlocking paver wall at my house in Bonny Doon stood out like a sore thumb and I wanted moss to grow over the concrete blocks like it did on the fieldstone retaining walls. I still remember looking back at the wall after painting on the moss/buttermilk mixture ala Martha Stewart’s instructions and seeing Sherman licking it all off. Even adding hot sauce to the mixture didn’t slow him down but I guess enough moss spores survived as the wall looked pretty good during the wet season before last year. Now I’m not so sure what survived on the wall since the fire but I’ll check on it next winter after the rains start – fingers crossed .

Like everybody else I didn’t go many places in 2020 during Covid times so I fondly remember my trip to Poland years ago. I did a lot of bird watching, hiking and punting. The gardens in eastern Poland were spectacular. The soil there, deposited by glaciers, is rich with sediment and nutrients. Sunflowers border neat plots of cabbage, beets, potatoes, cucumbers, lettuce and leeks. Black-eyed Susan cover the hillsides with swaths of gold blooms. Berries such as currants, blueberry, blackberry and raspberry are grown in large plots and fenced with wire. Every 10 feet or so plastic bags are attached and wave in the breeze. I was told this keeps the wild boar, roe and red deer at bay.
Sure looked funny, though.

This is my 800th column for The Press Banner. The first came about this way. I typed up a sample column and marched into the editor’s office. I’ve forgotten his name but little did I know that he had taken horticulture classes himself and so had a soft spot for my idea to write a weekly gardening column. Next thing I know he says he wants 5 columns, 400 words each, excluding prepositions, on his desk by Friday and the column would be called ‘The Mountain Gardener’ and not ‘Ask Jan’ which I had suggested. I knew my father who always encouraged me to write would be proud. I was now a newspaper columnist.

Improving Your Garden in a Few Easy Steps

Abelia Confetti pairs nicely with the burgundy foliage of a loropetalum

By this time of the year, you probably have planted some new perennials for color in your garden. But if you look around and still feel something is missing the answer may be that your landscape needs more than color. As a landscape designer I am often called upon for ideas to create richer landscapes that provide four seasons of interest. Here are some tips I pass along.

A more sophisticated appeal and enduring quality in your landscape can be achieved if foliage color is used to complement, or contrast with, other plants within the design. This technique unifies the overall look while offering appeal throughout the season. One plant that would make this happen is Rose Glow Japanese barberry. Their graceful habit with slender, arching branches makes a statement by itself but it’s the vivid marbled red and pinkish foliage that steals the show until they deepen to rose and bronze with age. In the fall, the foliage turns yellow-orange before dropping and bead-like bright red berries stud the branches fall through winter.

Abelia Confetti closeup.

Abelia Confetti is another small shrub that can be used to unify your landscape. Growing only 2-3 ft high and 4-5 ft wide with variegated eaves and foliage turning maroon in cold weather. Abelia are adaptable plants, useful in shrub borders, near the house or as as groundcover on banks. White, bell-shaped flowers are plentiful and showy during summer and early fall.

Texture in foliage is very important in good garden design. Varying the size and shape of leaves creates diversity and variety among neighboring plants. Striking visual interest can even be achieved when working with two different plants with similar shades of green.

An example of this would be combining Gold Star pittosporum tenuifolium with grevillea noellii. The first has dark green oval foliage on 10-15 foot tall dense plants while the latter is clad with narrow inch-long glossy green leaves. Clusters of pink and white flowers bloom in early into late spring and are a favorite of hummingbirds.

Loropetaum chinense

Using the same plant shape throughout a landscape can create rhythm, balance and harmony and tie the entire design together. Forms and shapes of plants and trees can be columnar, conical, oval, round, pyramidal, weeping, spreading and arching. A loropetalum with its spreading tiers of arching branches could be repeated throughout your garden to create visual interest and balance. A dogwood tree could also repeat this same form as their branches grow horizontally.

Consider also layering plants to create a beautiful garden. From groundcovers all the way up to the tallest tree, natural looking designs mimic nature.

Don’t forget about focal points. This could be a Japanese maple cloaked by a wall of dark evergreens or a statue or pottery at the end of a long, narrow pathway. Focal points draw attention and even distract the eye from an unsightly view.

There are many solutions to make your garden complete. Consider using some of the above design elements to make your landscape beautiful.