Growing Dahlias

Dahlias are among the easier blossoming plants to cultivate in the garden. As natives of Mexico, they thrive in the Monterey Bay area climate and bring drought-tolerance as well.

As mentioned in today’s article about the upcoming sale of the Monterey Bay Dahlia Society, dahlias are available in many different blossom forms and colors and can be a fine addition to the garden.

This column offers basic practices for growing dahlias after you have selected tubers at the Society’s sale.

The first consideration is to select a location will full exposure to the sun and good drainage. Dahlias, like most flowering plants, grow best with six hours of sun each day, and in well-drained soil. Sandy loam is fine, but clay soil will require substantial amendment with organic material.

Dahlia with Bee

Dahlias can be planted any time between the last day of frost (which is not a concern in this area) and as late as mid-June. The local tuber sale is scheduled around the time when last season’s tubers are ready to be dug and divided, so the day of the sale represents a good beginning for the local planting season. If you are not ready to plant, store your new tubers temporarily in a cool, shady environment.

Most dahlias will need staking, so it’s a good practice to position a sturdy stake for each tuber, and to install the stake at the same time that you plant the tune. Inserting a stake later runs the risk of stabbing the tuber.

If you don’t want bare stakes in the garden while the plant develops, you could install a short piece of plastic pipe with the top at ground level next to the tuber, then, when the plant grows to need staking, insert a thin stake (bamboo?) in the plastic pipe and tie the plant to the stake.

Plant the tuber several inches deep, with the “eye” (the growing point) facing up. Some tubers might lack such an eye, and will not sprout, but well-selected tubers will have viable growing points. The eye can be difficult to confirm, so selection can require some experience in identifying tubers that are ready to grow.

Separate the tubers from each other by about two feet.

Protect the sprouting plants from snails and slugs. A good practice is to visit your plants in the night (with a flashlight) or in the early morning to remove any crawling pests that have discovered them. Regular applications of an organic snail control, e.g., Sluggo, also works.

Control flying pests with insecticidal soap or other organic pesticides.

Generally, soil with ample organic content will provide sufficient nutrients for dahlias. If your soil seems “lean,” regular applications of high-nitrogen, organic fertilizer would be helpful.

As each plant grows, tie it to a stake to ensure that it remains upright. The first tie should hold the main stalk loosely to the stake; later ties could connect branches to the stake.

Each branch generally will produce three buds. To produce large blossoms, many gardeners remove two of these buds when they appear. This disbudding process allows the plant to direct nutrients to the remaining bud, with positive effect. If you have several dahlias growing in the garden, you will still have lots o blooms.

At the end of the season, the top growth dies back, and the plant produces several new tubers. The gardener can remove the top growth, and can either dig and replant the tubers or leave them in the ground. In the Monterey Bay area’s moderate climate, dahlias grow quite well when simply left in the ground. After two or three years, they will become crowded and will benefit from dividing.

Enjoy your dahlias! They are wonderful additions to the garden.

Communing with Nature

Good gardening practices almost always equal “working with Nature.” That is simply because natural processes have emerged after many eons as the Earth’s flora and fauna developed strategies for successful survival and propagation.

We write “almost always” from an excess of caution: it would be safe to say “always,” except for the use of the slippery term, “good.” The term “best” would also be debatable.

Still, all gardening practices that are beneficial for air, water, soil, plants and animals turn out to be time-honored, natural practices.

Not surprisingly, these practices are also beneficial to the gardeners, because we are also members of the animal kingdom, and tool-users as well.

Some of the gardener’s benefits are physical: everyone can gain health from exercise that is appropriate to one’s age and ability. Some are economic, providing either an inexpensive form of recreation or, for those with backyard nurseries, supplemental income.

Most benefits, however, are psychological, generating positive feelings, mental peace (according to Denver anxiety therapist), and the release of “happy hormones,” e.g., serotonin and dopamine. Admittedly, the latter benefit could be called a physical benefit, but it affects the psyche.

Working with Nature, therefore, works best for gardeners and literally everything in their surroundings. This concept can and should guide the gardener’s response to questions that arise in the garden. “What would Nature do about [insert gardening issue here]?”

This concept also works in reverse. Many commercially motivated gardening practices might appear to save time or increase productivity, but they often create harm in the long run, and sometimes even in the short run.

The worst of these practices involves bringing synthetic chemical fertilizers or pesticides into the garden. Non-toxic, effective organic products are readily available and should always be preferred.

Another avoidable and unnatural practice is the use of power tools in the garden, with gas-powered devices being the most problematic. The most common of these are gas-powered leaf blowers, which contribute faster than cars to climate change and air pollution and disturb the peace that we value in our gardens and neighborhoods.

The usual arguments favoring leaf-blowers include (a) our desire for tidy surroundings and (b) the operator’s interest in making the surroundings tidy as quickly as possible.

We should acknowledge, firstly, that Nature is not tidy. When trees drop their leaves in natural surroundings, the leaves decompose in time and add nutrients to the soil. When trees drop their leaves on pavement, we perceive untidiness. This suggests that we should plant trees only where their leaf drops would be beneficial.

If that is unrealistic (many people like street trees and patio trees), we should use manual methods to remove dropped leaves. Rakes and brooms work quite well, and in capable hands can be as efficient as leaf-blowers, and certainly much easier on the environment and our psyches.

Ken Foster of Terra Nova Landscaping demonstrates an alternative to leaf blowers. Photo by Dan Coryo, Santa Cruz Sentinel

Ken Foster of Terra Nova Landscaping demonstrates an alternative to leaf blowers. Photo by Dan Coryo, Santa Cruz Sentinel

For these reasons, many communities have already banned gas-powered leaf blowers, including Carmel and Santa Barbara to our south, and Palo Alto, Los Altos, and Menlo Park to our north. The Santa Cruz Coalition for a Healthy and Safe Environment (CHASE) has launched a petition favoring a local ordinance to ban these unnecessary and harmful tools. Check it out at .


Succulent Dish Gardens

While the rain soaks your garden, there still good ways to explore the world of horticulture. Planning landscape improvement and browsing the Internet for ideas or answers to questions both can be rewarding.

Developing a dish garden is a third option, one that involves actual gardening, albeit on a small scale.

Dish gardening can be enjoyed at any time, but it’s well suited as a rainy-day activity: it requires little time or space, yet it invites the application of gardening knowledge and aesthetic sensibilities.

A wide range of plants could be placed in a dish garden. Generally, good choices include plants that produce small leaves, grow slowly, and will thrive in the environment intended for placement of the finished garden.

Plant selection determines the design of the project, which might emphasize foliage, color, shady setting (e.g., a moss garden), a miniature landscape (e.g., a fairy garden), a Zen garden, a rock garden, cacti, or succulents. For inspiration, browse to Pinterest and search for “dish-garden” or “succulent dish garden” or other design concepts.

Here are two very different examples

Zen Dish Garden

Zen Dish Garden




Succulent Dish Garden

Succulent Dish Garden







This article focuses on succulent plants, which have good form while young, and many will either stay small or grow slowly.

Start by selecting plants. If you are already growing succulents, you will have ready access to small plants or cuttings that will root easily in a dish garden. If you don’t have sufficient succulents, small plants are readily available at garden centers. Gather plants with a specific grouping in mind.

Another important consideration is container selection. Dish gardens usually are placed in shallow containers; they provide enough root room for small plants, and they are lightweight enough to move easily. Bonsai containers work well, but any container could be pressed into service. Even actual dishes could be used, but they could be tricky to provide ample soil and to water without drainage (water lightly!)

As a practical matter, choose a container that will fit in the location intended for the finished dish garden.

Once the plants have been placed, parts of the planting surface might remain exposed. These areas could provide an aesthetically desirable context for the plant, like “white space” in graphic design. They could be covered by a top dressing that would complement the design: sand, pebbles, gravel, and decorative rocks are popular options.

Non-plant elements are optional. Some designs call for the inclusion of natural components, e.g., rocks, driftwood, shells, etc. They should be selected for their attractive character because they will be viewed close-up.

Some designs require artificial decorative items for completion or enhancement. Such items should be selected and placed as integral components of the design, rather than included merely because they are cute or colorful.

It is at this point that we note that personal preferences are of paramount importance. Dish gardens are, after all, expressions of an individual’s creative ideas, so whatever pleases the dish gardener stands as a success.

So, when weather frustrates your gardening goals, consider dish gardening as an indoor alternative.

Spring is the Time for New Plants

The first day of spring, astronomically speaking, will arrive on March 20th. It’s time to think about planting for the spring.

Actually, as we’ve noted more than once, the fall months are the best time for planting, to allow time for root development before the warmth of spring awakens the plants. The coming of spring might be regarded more as the traditional time for planting because that’s when the first tastes of warm weather awaken the gardeners.

The garden centers and online nurseries are oriented to the spring rush of gardeners seeking a few floriferous features for their gardens. The surge of mail-order catalogs and magazine galleries of new introductions manifests this orientation.

It can be quite interesting to peruse the new plants that are offered at this time each year. There are many familiar favorites, but the real headliners are plants that have been recently discovered by plant hunters or created by hybridizers.

Some plant hunters roam the globe in search of garden-worthy plants that have not been seen in their natïve lands. The history of gardening includes a long list of plant hunters who have served to relocate plants from exotic places to the gardens of Europe and, more recently, the United States. The best known of the contemporary plant hunters is Daniel Hinkley who shares his travels and horticultural discoveries in his books and articles in Horticulture magazine and other periodicals. Check out his website.

Plant hunting doesn’t always require traipsing through distant lands. New discoveries also can be made by close observation of large groups of plants in cultivation. As plants pollinate each other, potentials exist for mutations or “sports” to appear with novel characteristics. Because these natural changes are random rather than evolutionary, they will include a significant percentage of uninteresting innovations, but occasionally a natural mutation results in a desirable variation of a familiar plant. Then, the grower’s role is to propagate the newcomer to produce enough plants for commercial distribution, come up with an appealing name for the plant, and introduced it into the trade.

A third approach to developing new plants involves hybridizing. The process is quite simple, at its core: the hybridizer selects two plants of the same species with different but desirable traits. For example, one might have a good blossom color and the other might have strong stems. The hybridizer transfers pollen from one plant to the other, plants the seeds that result from this mating, and examine the seedlings for the desired combination of traits. Typically, the hybridizer will reject many of the seedlings as unsuccessful relative to the objectives, and, with luck, will find one or more successful results. These are propagated further for commercial distribution.

Given the uncertain outcomes of this process, it requires time, patience, and good record-keeping to result in a financial payoff.

This brings to mind the secret to making a small fortune in the plant breeding business: begin with a large fortune.

The process of finding or creating new plants always targets the individual gardeners who want to add the latest introductions to their gardens. One that has caught my eye is a Sempervivum hybrid ‘Gold Nugget’, available from ChickCharms, which specializes in collectable hens & chicks. It’s a little pricey but quite striking.

Sempervivum 'Gold Nugget'

Sempervivum ‘Gold Nugget’






The gardener might enjoy bringing new introductions to the landscape but could also stay with familiar and reliable options. Either way, enjoy your garden!

Sanctuary for Hummingbirds

If you are a hummingbird, the University of California’s Arboretum provides an excellent home territory. During tomorrow’s Hummingbird Day at the Arb, you can see the hummers enjoying this local sanctuary.

Anna's HB - Female at Grevillea 300 pixels

Anna’s Hummingbird (female) at a Grevillea







Consider the threats to the hummingbird’s life and limb (make that “life and wing”).

Habitat Loss

All of nature’s flora and fauna depend on the surroundings of their native environment. They have evolved to consume familiar food sources and enjoy safe places for shelters and nurseries for their young. Too often, human encroachments have converted such environments through urbanization, agriculture, and logging, leaving the denizens of the wild to retreat into smaller and smaller areas.

The hummingbirds’ challenge in finding an appropriate place to live resembles that of people looking for affordable housing in the San Francisco and Monterey Bay areas.

Long ago, hummingbirds discovered the Arboretum as a fine place to find nourishment and safety, and to raise baby hummingbirds.

They found one significant complication to the sanctuary they discovered: the Arboretum has lots of California native plants that the hummers know best, but this place also grows many plants that thrive in Monterey Bay area’s climate and the Arb’s soil, but are California exotics. The native plants of Australia, New Zealand and South Africa contribute to the Arboretum’s unique collection, which fascinates its many human visitors, but puzzle the hummingbirds.

Happily, hungry hummers have adapted to this special situation: they have grown to love many of the Arboretum’s plants. They show great appreciation for the Australian collection, and have made particular favorites of the Grevilleas and Banksias.

Grevillea 'Robyn Gordon' 300 pixels

Grevillea ‘Robyn Gordon’ – a hummingbird favorite







Pesticide Poisoning

Pesticides provide another important threat to the hummingbirds. Pesticides include synthetic chemicals that kill plants, animals and insects that damage both crops and ornamental plants. Too often, these chemicals unintentionally kill desirable and beneficial flora and fauna, as well. For example, bee colonies have been damaged greatly by exposure to such chemicals.

Hummingbirds, too, are susceptible to chemical poisoning. Their small size and rapid metabolism makes them vulnerable to even small direct exposures to toxic materials.

Pesticides also have indirect impacts on the wellbeing of hummingbirds by killing insects that are an essential source of protein. Hummingbirds are carnivorous, eating insects that they snatch out of the air, pluck from foliage, or glean from spider webs. Hummers could not live on sweet nectar alone.

The Arboretum’s historic avoidance of synthetic pesticides adds substantially to its quality as a hummingbird sanctuary. The Arb’s insects, plants and indeed the soil are naturally clean and safe for hummingbirds.


Feral cats represent a third threat to hummingbirds, as well as to other birds and small mammals. Cats are favored companions for many people, and friendly in their aloof way, but in their wild selves they are fierce predators, with birds as their preferred prey. Unlike other birds, hummers occasionally hover close to a nectar-filled flower cluster. If that cluster is fairly close to the ground, the bird becomes an easy victim of a crouching feline, which could kill a tiny hummer with one swipe.

The Arboretum asks its human visitors to not bring pets with them to view the collections. This ban focuses on dogs and certainly includes cats, although few people take their cats with them for outings. The Arboretum, being a natural environment at heart, is visited occasionally by mountain lions, but those noble creatures are unlikely to feed on hummers, and more likely to discourage visits by feral cats.

Hummingbird Day

Two genera of hummingbirds visit the Arboretum; both are members of the family Trochilidae, which includes a large number of hummingbird genera from the Americas.

The Anna’s Hummingbirds (Calypte anna) are permanent residents of the Pacific Coast, and the Allen’s Hummingbirds (Selasphorus sasin) spend most of the winter months in the mountain forests of Mexico and migrates to northern California during breeding season, from January through March.

Allen's - male HB at rest 72 pixels

Allen’s Hummingbird (male), at rest


Anna's - male HB - at rest 72 pixels

Anna’s Hummingbird (male) at rest








The Arboretum schedules its annual Humming Day to coincide with the combination of breeding season and the arrival of the Allen’s Hummingbird. This is prime viewing time for hummingbird watchers, who can enjoy two eye-catching activities.

First, the Allen’s Hummingbirds tend to be very territorial, so their arrival leads to aerial battles with the resident Anna’s Hummingbirds, who have been simply minding their own business.

Then, for the hummers’ breeding season, the males display unique courtship antics, with amazing steep dives toward a targeted female, culminating in sound effects: male Anna’s make an explosive popping sound; and male Allen’s produce a metallic whine. Later in the season, while the females are feeding their young, there is a good deal of swooping about to collect insects to bring to their nestlings.

As a result of these two activities, during which the hummers ignore their human observers (while staying safe), Hummingbird Day is a great opportunity to see the aerial stunts of these exceptional flyers.

The event, which is each year’s most popular occasion to visit the Arboretum, happens on Saturday, March 4th, and includes guided tours, talks on hummingbird gardening and photography, and special craft activities for children.

Young visitor with a hummingbird toy

Young visitor with a hummingbird toy








Hummingbird Day is one of the Monterey Bay area’s most unusual and most enjoyable encounters with wildlife. Be sure also to browse the plant collections during your visit.


What: The annual celebration of hummingbirds. Walking tours, talks, and children’s activities with a hummingbird theme.

When: 10:00 a.m. to 4:00 p.m., Saturday, March 4th

Where: UC Santa Cruz Arboretum, on Arboretum Road, west of Western Drive

Cost: $10 for public; $5 for members of the Arboretum; free for UCSC students and children under 12

Parking: Free

Information: Visit the Arboretum’s website.