Tag Archives: gardening tips

Plants that Hold up in the Heat

What happens to a plant when the thermometer tops 100 degrees like it did a couple weeks ago? 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?

Bees Bliss salvia

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 hight 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. In my own garden I grow several plants that are doing quite well without irrigation and handled the heat wave just fine. One is Bees Bliss Sage, a low groundcover that can reach 6-8 ft wide draping over rocks and walls. 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.

salvia clevelandii

Another plant that can handle high temps is salvia clevelandii. Right now it has just started its blooming cycle of electric blue-purple flowers. They will last through the summer. This salvia survives without any supplemental irrigation but if I give it an occasional deep watering and wash off the foliage every so often its much happier.

mimulus arantiacus

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.

As summer comes along the California fuchsia will provide the color in the garden. I like it that they spread by underground rhizomes and self sow. Free plants are always welcome. I have them planted on a slight slope where they tumble over a rock wall. My bees and hummingbirds find this plant irresistible.

penstemon heterophyllus

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.

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.

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

Tips for Planting Success

With our gardens coming to life at this time of year we are hopeful that each plant will achieve its full potential during this growing season. But that doesn’t always turn out to be the case and sometimes it’s hard to figure out what exactly is the problem. Growing plants isn’t an exact science. What works over at the neighbors yard doesn’t always apply to ours. What are the different factors that makes a plant thrive or just mope along? And how can you plan when one source shows the plant’s size at 6 feet tall while another has that same plant as 8-12 ft tall and just as wide? What’s a gardener to do?

Callistemon ‘Little John’

When designing a garden, whether it’s for a client or my own garden, I take into account the growing conditions such as soil type and fertility, winter low temperature, space and light. All plants need water to carry moisture and nutrients back and forth between the roots and leaves. Some need more water than others to do this but all have their own levels of tolerance. Too little or too much water can be harmful to your plant’s health.

Choosing the right plant for the right spot is another important factor. How do you determine if your garden has the right amount of sun or shade? In our area a good rule of thumb in deciding if your plant is getting enough or too much sun is to note how many hours of full sun, part sun or bright shade your area is receiving during the middle of the day. Too little light can make plants weak and leggy looking with few flowers or fruit.

Most plants enjoy morning or late afternoon sun. Winter conditions are not always as important as those of the summer. Then again if your area gets no winter sun and your soil is heavy clay that sun-loving native plant might not survive. Sometimes it’s complicated.

Grevillea lanigera ‘Mt Tamboritha’

Allow enough space for your plant to grow. Plants can become stunted without enough room to grow and overcrowded plants often get diseased when air doesn’t freely flow between them. There’s a difference in a plant that just needs a little time to kick in and really start growing and one that is not thriving. Be patient.

Plant your new addition correctly. Dig the planting hole at least twice as wide as the container but no deeper than the depth of the root ball unless the soil is deeply compacted. Leaving the bottom of the hole undisturbed helps prevent the plant from settling below its root crown. In soil containing a high percentage of clay, score the sides of the planting hole with a shovel to aid root growth outward from the hole.

It’s best not to add soil amendments or fertilizers directly to the planting hole, although it may be beneficial to spread some well composted manure to the surface before digging the hole. Wait until new growth is several inches long before applying fertilizer.

Planting a bit higher than the surrounding soil allows for a 2 inch thick layer of mulch around the plant but don’t bury the crown. After planting don’t till the soil again allowing the beneficial organisms to re-establish.

If you have a steep hillside, a super sunny or deep shade location or problem soil the above tips are even more important for your planting success.

Garden Tasks-Rain or Shine

Those of you who lived in the Santa Cruz mountains during the winter of 1982 remember it well. Following two days or torrential rains, a large section of hillside above Love Creek gave way. Thirty homes were destroyed and ten people were killed by the slide. The rainfall totaled 111 inches that year.

Rain gauge on 2/8/17 showing 99.99″ +10″ more as of 2/18/2017

During the winter of 1997 the San Lorenzo Water Department recorded 90 inches of rain. The department’s historical rainfall data goes back to 1888 and shows that during the winter of 1889 a whopping 124 inches of rain fell. This winter is one to rival the books with about 70-110 inches of rain falling so far depending where you live. We don’t aspire to break any records.

How does this much rainfall affect our gardens? If you have addressed drainage issues and are slowing, spreading and sinking all this water, congratulations. But what about the plants? Fortunately most plants are dormant or semi-dormant at this time of year. Even plants that don’t lose their leaves aren’t in growth mode yet. When a plant is actively growing either roots or new foliage it will suffer if the roots are soggy day after day. Fungal problems and root rot will take its toll on a plant. An extremely wet March or April is not a good thing.

We gardeners are the eternal optimists and hope that only gentle rains will fall through May. And during those lulls in the weather this is what I’m going to be doing over the next month.

California fuchsia – zauchneria californica

Prune fruit, nut, shade trees and deciduous vines like clematis. Cut back woody shrubs like Mexican bush sage, artemisia and butterfly bush to stimulate lush new growth. You can cut back these plants close to the ground. Don’t use this approach on lavender or ceanothus, though. Prune them lightly after blooming without cutting into bare wood.

Prune fuchsias back by a third and remove dead, crossing branches and interior twiggy growth. Container fuchsias can be cut back to the pot rim.

mophead hydrangeas in June

Cut back hydrangeas stems that bloomed last year and apply a soil acidifier if you want the flowers blue. Although sulfur is the traditional favorite for quickly acidifying soil it is not as kind to many beneficial soil microorganisms. Coffee grounds, pine needles, peat moss and cottonseed meal are better for your soil.

I’ll wait to prune back perennials that may have their new foliage damaged in a late frost. Already damaged foliage can protect a plant from further frost damage. Mid-March is the estimated date of last hard frost in our area. Or at least it used to be.

Don’t cut back grasses yet if you get frost in the area where they grow. Wait until mid-March. If you live where you rarely get frost go ahead and prune these plants back now. I’m going ahead and pruning California fuchsia, salvia ‘Bee’s Bliss’ and hummingbird sage now. They look terrible.

camellia sasanqua

Don’t prune spring flowering shrubs and trees like lilacs, flowering cherries, plums and crabapples, rhododendrons, azaleas, camellias, weigela or spirea until after they flower. You can cut some branches during flowering to bring in cuttings for bouquets.

I can tell that spring will soon be here as the flowering plum buds are showing color. Can’t tell from the weather report, though.

About Roses

Roses are the flower of love. Many of us have fond memories of favorites in our mother’s garden or of a beautiful bouquet given or received on Valentine’s Day. It’s dormant season for roses which is good for both pruning and adding a few to the garden.

David Austin rose

As a designer I have clients who have inherited roses and want to keep them as a remembrance. Others want to create a cutting garden filled with roses and other perennials. Don’t feel guilty for growing those beauties in your own garden. They use less resources than you think and there are many ways to grow them sustainably.

Roses, whether bush types, climber or ground cover carpet varieties, use a moderate amount of water in order to thrive according to the latest Water Use Classification of Landscape Species (WUCOLS) list. This amount of summer irrigation is the same as many of the plants on the list of Scotts Valley Water District’s 800 Approved Low Water-Use Plants for lawn replacement. Plants such as Emerald Carpet manzanita, Joyce Coulter ceanothus, Siskiyou Blue fescue grass, Pacific wax myrtle, butterfly bush, yarrow hybrids and Tapien verbena have similar water requirements.

Since now is the time to prune your roses here are a few tips.

Strike it Rich hybrid tea rose

Prune shrubs moderately to keep them compact. The goal is to keep the center of the plant open for good air circulation aiming for a vase-shaped bush with an open center. Cut out canes that cross, appear weak or are diseased, spindly or dead. Healthy canes appear green or reddish while old and dying canes are brown. Cut back the remaining stems by about one third. When pruning, cut canes at a 45-degree angle just above an outward facing leaf bud or a swelling on the cane. Clean pruners after every use to prevent the spread of disease and keep your pruners sharp.

Prune heirlooms roses such as David Austin and other old antique garden roses less because their open look is part of their charm.

Same goes for climbing roses. Cut out extra stems if there are too many and also cut back long established canes to about the place where they are slightly thicker than a pencil. Then cut each side stem down to several inches. This will make the cane flower along its complete length for a beautiful spring display.

Zepherine Drouhin climbing rose

Pluck off and rake away any old leaves. They can spread fungal spores. Consider spraying dormant plants with a combination of organic horticultural oil and copper soap or lime-sulfur. If you usually only have problems with black spot you can use a mixture of 1 teaspoon baking soda with a few drops of light horticultural oil in 1 quart water and spray every 7 to 10 days during the spring.

Prune your roses throughout the growing season, too. Deadheading, or cutting off spent flowers, encourages plants to re-bloom. Mulch around your roses to conserve water and encourage soil microorganisms.

Don’t worry whether you’re pruning job is perfect. Roses are super forgiving and you can always trim them up again later.

Late Summer Tasks for the Garden

It’s darker in the mornings now with the sunset coming earlier each evening. All that time I thought I’d have back in June to get things accomplished in the garden has vanished in what seems like a wink of an eye. Still the weather these days is perfect for being outside and pecking away at my to do list. There are also some late summer/early fall tasks that need attention.

alstroemeria_variegated
Alstroemeria ‘Rock & Roll’

Now through October, divide summer blooming perennials like alstroemeria, agapanthus, coreopsis, iris, daylily, yarrow, rudbeckia, calla lily, aster and penstemon that are overgrown and not flowering well. You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart although they don’t always bloom the first spring afterwards due to the energy they use re-establishing themselves. Start perennial flowers seeds now so that they will be mature enough to bloom next year.

This is the perfect time for transplanting or adding new plants to your garden. Why? Cooler air is kinder to plant foliage and soil temperatures are still warm which creates an excellent environment for new root growth. In the fall many plants and trees, even broadleaf evergreens, are entering a period of dormancy. With no need to allocate resources into foliage, plants are transferring all their energy into roots and storing nutrients for the cool months ahead. By spring, the new roots system should be well established.

Perhaps it’s time to remove or reduce lawn. Replant with more drought tolerant ornamental grasses or perennials.

achillea_pink
Achillea millefolium

Fertilize shrubs lightly one last time with an all-purpose organic fertilizer or layer of compost. This advice doesn’t apply to California natives. They like compost only around the roots during the winter while they get ready for their growing season.

Roses especially appreciate a bit of fertilizer now, encouraging them to bloom another round in the fall. To keep them blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new flower bud to grow much sooner than if you cut to one with only three leaves.

Plant cool season veggie starts like broccoli, cabbage, cauliflower, chard, lettuce, spinach, brussels sprouts, onions and leeks in soil enriched with 4-6″ of compost as summer vegetable crops will have used up much of your soil’s nutrients.You can sow seeds of beets, carrots, radishes, spinach, arugula, mustard and peas directly in the ground.

soil_builder_cover_crop_mix-1600
Soil builder cover crop mix

If you aren’t going to grow vegetables in the garden this fall consider planting a cover crop like crimson clover, fava or bell beans after you’ve harvested your summer vegetables.

Cut back berries vines that have produced fruit. Canes of the current season should be trained in their place.

Spider mites are especially prolific during hot, dry weather. Sometimes you don’t even know how bad the infestation is until all your leaves are pale with stippling. Periodically rinse dust and dirt off leaves with water. Spray the undersides of infected leaves with organics like insecticidal soap switching to neem oil if they build up a resistance to one of the pesticides.

And whatever you do, enjoy being outside in this beautiful place we call home.

Troubleshooting Plant Problems

Troubleshooting is a form of problem solving. And whether it’s a car problem, your smart phone, an irrigation system or yellowing leaves on a plant the goal is to solve it and make the product or process operational again. When you eliminate the potential causes of the problem hopefully the solution restores everything to its working order. Sounds like something Sherlock Holmes would say and it’s sometimes easier said than done as we all have experienced.

burned_heuchera_leaves
sunburned heauchera leaves

A few weeks ago I received a text with pictures of some plants with brown spots and asked what I thought might be the problem with their plants. This was after the heat wave we experienced and after asking a few questions about irrigation, location and how long the plants had been in the ground, I determined that the plant leaves had been burned in a pattern consistent with the location of the beating sun. At this time of year plants are growing wildly and need a good soak moistening the entire root zone. The solution: Better to water deeply less often than lightly which might not reach all the roots.

The subject of how much fertilizer and what kind came up in another troubleshooting email thread between some fellow horticulturalists. The issue was whether to use another round of organic high phosphate fertilizer in order to encourage bud development on a notoriously short-season tree dahlia. After some lively discussion we decided that the early spring application of rock phosphate was sufficient. Sometimes adding too much phosphorus may actually hurt a plant by preventing the uptake of other nutrients which must also be available to the plant in order to prevent unexpected deficiencies to appear. A balanced fertilizer containing all three nutrients- nitrogen, phosphorus and potassium-was recommended for the remainder of the season.

yellow_lemon_leaves
yellow leaves on lemon

Then there were some problems in my own garden. Well, it seems I am always trying to solve something with plants, pests or critters but this was with my lemon tree. At first I was perplexed when the older leaves of my lemon tree started turning yellow a couple months ago. The new growth looked fine so it wasn’t an iron deficiency where the young leaves display green veins along with the yellowish color.

It wasn’t a nitrogen deficiency either where the mature leaves slowly bleach to a mottled irregular green and yellow pattern, become entirely yellow and then are shed while the discoloration spreads to the younger leaves. I had fertilized in March with an all-purpose balanced fertilizer. Citrus are heavy feeders and require a steady source of nitrogen, the ideal citrus fertilizer having a ration of 3:1:1 (N:P:K)

After eliminating other mineral deficiencies or overwatering as the problem I decided that my lemon was simply dropping interior leaves which is normal after winter but I wanted to trouble shoot all potential causes to be sure citrus greening wasn’t the culprit. If it had been this deadly disease the leaves would have exhibited an asymmetrical pattern.

To quote Sherlock Holmes “Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.” I’ll try to remember that when I’m troubleshooting my next problem in the garden.