All posts by Jan Nelson

I am a landscape designer and consultant in the Santa Cruz mountains in California. I write a weekly gardening column for the Press Banner newspaper. I am also a Calif. Advanced Certified Nursery Professional and managed The Plantworks Nursery in Ben Lomond, Ca. for 20 years.
Design trends

Watering Tips for Hot Weather

De la Mina verbena is a California native that blooms spring to fall. Water when the top 3 inches of soil is dry.

After a lovely, mild spring, summer weather arrived with a vengeance. My poor plants were thinking they lived in England and then were rudely awakened and reminded that they actually live inland and away from the influence of the cool coast. My watering schedule and methods have changed and I’m reminded of some tips that will make all the difference in my plants’ performance this summer.

After you’ve chosen climate adapted plants how much water do they really need? Here’s how can you keep everything happy and not waste water.

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 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 about 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 restrictions. 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 waterings 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.

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 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 wouldn’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.

Butterfly Bush are fragrant, too.

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.

With lots of mulch and the above watering tips you can keep all your plants happy and healthy.

Design trends

The Cutting Garden

The assignment: create a cutting garden. For a designer this is the best kind of request. 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. So if you picture yourself strolling out in your garden, bucket in hand to cut beautiful richly colored, fragrant bouquets for your own home or to give to family or friends here are some tips that will make that happen.

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 set 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.

All bouquets are beautiful.

Design trends

Gardening Tips for Sandy Soil

Common in the Santa Cruz mountains, Bush Poppy bloom readily in sandy soils.

Many years ago I started writing a book about Gardening in the Santa Cruz Mountains. One of many interesting subjects I researched was the different soils we have here in the mountains. I don’t need to tell you if you garden in dense clay, serpentine soil or that sandy soil like being at the beach that our soils are challenging. That sandy soil? Well, it’s because we used to be a beach eons ago before the land rose up out of the sea. Here are some tips for those who live with sandy soil.

The distinct region of the Santa Cruz sandhills, with its gritty, well-drained soil, presents both opportunities and hurdles for gardeners. Here’s how to turn your sandy soil into a thriving garden?

Sandy soil is composed of larger particles compared to clay or loam, meaning it drains quickly and doesn’t retain nutrients well. This is not a death sentence for your garden. You can transform your terrain into a lush, productive garden with just a few steps.

Start by improving your soil’s structure. Organic matter is your best friend. Compost can really boost your soil’s
ability to retain moisture and nutrients. Regularly adding organic matter will gradually improve its texture and fertility. Do this every year. Cover crops, such as clover or fava beans, can be very beneficial. They not only add organic matter to the soil when turned under, they improve soil structure and even fix nitrogen, enriching the soil for your plants.

Low water use Fremontodenron grow well in sandy soils.

Choose plants that will thrive in sandy, well-drained soil. Native plants are good choices as they are adapted to our local conditions. I see Bush Poppy (dendromecon rigid ) thriving in the most inhospitable of places. Plants from the Mediterranean area and Australia are also good. Manzanita and ceanothus thrive in sandy soils. Rosemary, lavender and thyme do well in porous soil and are fragrant. Salvia, buckwheat, yarrow are easy to grow in sandy soils. Carrots, radishes and potatoes are ideal for sandy soils because they prefer loose, well-draining conditions. Be sure to provide plenty of organic matter and mulch to help retain moisture around your plants.

One of the main challenges with sandy soil is water retention. Water wisely, frequent, shallow watering won’t work here. Instead, water deeply and less often to encourage plants to develop deep root systems. Drip irrigation systems can be particularly effective, delivering water directly to the plant roots and reducing evaporation. Mulching is another critical practice. A thick layer of mulch helps retain soil moisture, suppresses weeds adding organic matter to the soil as it decomposes.

Because sandy soil doesn’t hold nutrients well, regular feeding is important. Organic fertilizers like compost tea, fish emulsion or seaweed extracts are great for providing a steady supply of nutrients. Slow-release granular fertilizer is also good.

The natural beauty and unique characteristics of the sandhills can be enhance by incorporating elements that blend with the landscape. Rock gardens, succulent beds and native grasses can create a stunning, low maintenance garden that harmonizes with the environment.

By understanding and working with its unique characteristics, you can cultivate a thriving garden even in the Santa Cruz sandhills.