Creating a Garden Map

Creating a record of the plants in your garden yields several benefits. A “garden record” includes two essential components: the name, photo and basic cultivation notes for each plant, and an indication of each plant’s location in the garden.

A more elaborate plant record could include extensive plant info that reflects the gardener’s interests. Examples include purchase details (when, where, cost); native region; and landscaping ideas. The record could be extended further with notes on the plant’s development over time, including bloom times, pruning, propagation, fertilization, etc.

Such details, while relevant, are the territory of professional growers and very zealous gardeners.

The minimalist approach to a garden record involves simply inserting a plant tag in the soil next to the plant. A respectable tag from the nursery provides the plant’s botanical and common names, plus a phrase about its mature size and growth needs. Placing the tag in the soil marks its spot in the garden. This method, although popular, has notable shortcomings: sparse information, ephemeral mark of location, and plastic intrusion into the natural setting.

Plant tags are best used for temporary reference, during the preparation of a better garden record.

After considering those extreme forms, let us return to the fundamental model of the plant record.

Plant Information

Compiling information on an individual plant can be accomplished most easily and quickly with an Internet search, using the plant’s botanical name, or, if necessary, its common name. This information should be available on the plant tag.

The first search should be the website of the nursery that grew the plant. The nursery’s name could be read from the plant tag, or provided by garden center that sold the plant.

Other good sources include San Marcos Growers in Santa Barbara. SMG grows many plants and supplies them to garden centers. Their website (includes a fine database of plants that they grow —or used to grow— with photos and detailed descriptions, cultivation suggestions, and notes on the plant’s discovery or hybridization.

More good online resources include Wikipedia for plant information and Wikimedia Commons for plant photographs.

Other websites with useful plant information could be discovered through a botanical name search.

After locating basic plant information, good practice involves developing a database of plants in your own garden. This could be accomplished on paper or in digital form, i.e., as a computer file. Organize the plant under discrete planting beds or areas of the garden.

Garden Map

The second component of the garden record is a map showing the location of each plant in the database. Plant locations could be documented with notes within the plant description, but a graphical map would be a more useful reference for monitoring plant growth and developing the landscape development.

The garden map need not serve as an artistic triumph or an exercise in precise engineering, but it should amount to a scale drawing of the garden area. For a garden on a standard lot with a typical complement of plants, a map of the entire garden could be sufficient. For larger gardens, or those with many plants, a series of maps representing areas of the garden would support notations indicating plant locations.

On the map, represent each plant with its name, or a numeral linked to the plant record, or a numeral linked to symbol. The symbol could be a circle of appropriate size, or, for the artistically inclined, a simple drawing that suggests the size and form of the plant.

Again, primary purpose of the garden map is to document plant locations, rather than to create a work of art.

The map must be editable, so that it could be updated to reflect additions, deletions, and relocations of plants. Working in pencil could be most appropriate.

A garden map also could be created and maintained as a digital file. This method involves the use of computer graphic software, either a general purpose or garden-mapping application. This column cannot include an overview of garden mapping software, but, generally, the garden-mapping software that is currently available is intended for edible gardens in which plants grow in rows. Such software could be helpful for planning and describing traditional vegetable gardens, but is not suitable for ornamental gardens, or for edible gardens that are designed for aesthetic effect, including those that creatively combine edibles and ornamentals.

Graphic design software with the functionality needed to represent irregularly shaped planting beds is certainly available, but tends to require significant expense and skill.

Avid gardeners can develop plant information and garden maps to create garden records of substantial value in developing and maintaining the garden. Good practice suggests adopting readily accomplished formats, rather than aspiring to high standards that are unlikely to be achieved or maintained. The first priority should be to create the garden record as a practical tool for planning, developing and maintaining your garden.

The rainy season is a good time to pursue your garden record project!

Plants Preferred by Other Insects

In a recent column, we described the first report of the Royal Horticultural Society’s “Plants for Bugs” study, which focused on Pollinators. In this column, we’ll look at the second report of this study, “Gardens as Habitats for Plant-Dwelling Invertebrates” (August 2017), which is about insects and invertebrates that live in our gardens, and the plants they love.

Let’s first review the related taxonomic issues.

Gardeners should appreciate the difference between “bugs” and “insects.” The title of the RHS study uses “bugs” to refer informally to a large and diverse group of invertebrates. To be precise, true bugs are members of the order Hemiptera, which is within the class Insecta. There are some 50,000 to 80,000 species of true bugs, all of which have sucking mouthparts. Examples of true bugs include cicadas, aphids, planthoppers, leafhoppers, and shield bugs. By the way, none of the true bugs are pollinators.  

The Insecta is a class within the phylum Arthropoda, which includes 6 to 10 million species, all of which are hexapod (six-legged) invertebrates.

To put the true bugs in perspective, they represent only a tiny fraction of the Insecta.

Returning now to the RHS study, the first report addressed garden insects that are Pollinators, which include bees, butterflies, and a few other insects.

The second report addresses other significant categories of garden insects, which include these groups:

  • Herbivores. Invertebrates that feed on living plants, using chewing mouthparts (e.g., caterpillars) or sucking mouthparts (aphids are a familiar example).  
  • Predators. These are invertebrates that eat other invertebrates. These include lacewings, beetles, e.g., ladybirds, some true bugs, spiders, and parasitoid wasps, which kill their hosts.
  • Omnivores. These invertebrates feed on both plants and other invertebrates. This group includes the harvestman (a spider relative), earwigs, and aphids.
  • Detritivores. Invertebrates that feed on decomposing organic matter. Examples include springtails, woodlice, and some beetles.
Common Lacewing (Chrysopa species) photo by JJ Harrison, shared via Wikimedia Commons

These groups, along with the Pollinators featured in the first report of the RHS study, constitute a vital component of the garden’s balanced ecosystem. In addition to breaking down dead plant material, these plant-dwelling invertebrates provide food for other wildlife, including birds, reptiles, and small mammals.

In their four-year Plants for Bugs study, the RHS scientists used suction samplers to collect about 18,000 of plant-dwelling invertebrates. Their samples included 18% Herbivores, 3% Omnivores, 18% Predators, and 61% Detritivores. They also collected about 4,700 uncategorized invertebrates.

They recorded these collections of invertebrates separately from plants that were native to three different areas: the United Kingdom (called ”natives”), other areas in the Northern Hemisphere (“near natives”, and Southern Hemisphere (“exotics”).

As they found with Pollinators, the scientists found that the native plants supported the largest numbers of the plant-dwelling invertebrates. By comparison with the native plants, the near-native plants supported about 10% fewer invertebrates, and the exotic plants supported 20% fewer.

Overall, these observations indicated that native plants are most important in supporting these groups of invertebrates, and the near-native and exotic plants also provide effective support at somewhat reduced levels.

The study concluded that gardens should emphasize native plants, but could include near-native and exotic plants as well. The most important consideration was to develop a dense planting scheme so that the garden could support all kinds of plant-dwelling invertebrates as part of a balanced ecosystem.

Exotic plants are important to include in the garden for Pollinators because Southern Hemisphere plants often bloom during months when Northern Hemisphere plants are dormant, and thus provide Pollinators with food sources for a longer period of the year.

Although this study was conducted in England, its findings could apply reasonably also to gardens of the Monterey Bay area. With that interpretation, we would treat California native plants as the “natives,” plants from the Mediterranean climate areas as “near natives,” and any other plants as “exotics.”

These two studies support the usual assessment that native plants are most supportive of local plant-dwelling invertebrates, while showing that near-native and exotic plants also provide effective supports for the garden’s ecosystem.

These findings might apply as well to local birds, reptiles and mammals, but demonstrating those relationships would require another study. For example, while berry-producing shrubs provide natural food for birds, separate counts of bird visits to native, near-native, and exotic berry-producing shrubs might yield interesting results.

That would be a very challenging assignment!

Plants Preferred by Pollinators

When planning their gardens, many gardeners recognize the relationships between their plants and local wildlife. This ecological perspective has gardening implications for each of several categories of wildlife: birds, mammals, reptiles, and various invertebrates.

An overarching concept for this ecological perspective is the food chain. Insects are low on the food chain, so selecting plants according to the needs and preferences of insects has impacts on the higher levels of the chain. As a basic example, plants that attract insects to the garden increase the food source for birds and reptiles, and an increase in the numbers of birds and reptiles provides food for carnivores.

Gardeners often want to grow flowering plants that attract bees, butterflies, and other pollinators. Those gardeners might intend primarily to support plant pollination and garden aesthetics (butterflies always delight the eye), but their plant selection also supports the food chain. 

As we develop our garden and select plants from this ecological perspective, we might favor plants that are native to our local environment. The rationale for preferring native plants reflects an assumption that the insects and other wildlife in our gardens know and prefer plants that they have encountered throughout their lives, and the lives of their preceding generations. Surely, wild creatures communicate survival knowledge to their offspring at least by demonstration.

For such reasons, I have favored native plants because of their presumed appeal to local wildlife, in addition to the compatibility of native plants with native soil, climate, and plant communities. The logical application to this view is for the gardener to fill the garden with native plants.

This approach to landscaping succeeds. We are not here to negate gardening in the Monterey Bay area with California native plants.

I have become aware, however, of another layer of thought to consider.

In a recent issue of Horticulture magazine, entomologist Eric Grissell described a wildlife gardening study, “Plants for Bugs,” conducted by England’s Royal Horticultural Society.

I visited the project’s website to learn about this project. Its first bulletin for gardeners is titled “Gardens as Habitats for Pollinators” (August 2015). This column addresses the study’s methods and findings related to pollinators.

Honey bee (Apis mellifera) pollinates creeping thistle  photo by Ivan Leidus,
shared via Wikimedia Common

The study’s approach was to observe the numbers of times pollinating insects land on flowers of plants with each of three different origins: United Kingdom natives; other Northern hemisphere natives, i.e., plants from regions similar to the UK; and Southern hemisphere natives, i.e., plants from climates and habitats that are different from the UK.

The study’s original recommendations are oriented to the United Kingdom, but they could be applied reasonably to other gardening environs. Accordingly, I have modified the wording of these statements to relate them to gardening in the Monterey Bay area.

  1. Gardeners should plant a mix of flowering plants from different countries and regions;
  2. Plant selection should emphasize plants that are native to California’s central coast, or to the Mediterranean climate areas;
  3. Regardless of plant origins, the more flowers the garden can offer throughout the year, the greater number of pollinators it will attract and support.

Plants that are native to the garden area are still important, but gardens serve pollinators best when they have large numbers of flowers and a long flowering season, regardless of the origins of the plants.

In a future column, we’ll review this project’s second bulletin, “Gardens as Habitats for Plant-Dwelling Invertebrates” (August 2017).

Assessing a Neglected Shrub

A situation that could arise in any garden, including your garden: the gardener becomes aware of a shrub that has been neglected and that has outgrown its space and become rather misshapen. In addition, the gardener has lost track of the shrub’s name and can’t locate cultivation notes on the Internet.

I recently had such a challenge in my garden’s Australian bed. While I was not paying attention, a shrub grew to about five feet high and eight feet wide, and began crowding adjacent plants. In addition, it had been produces leaves and flowers at the ends of its branches, so that the interior of the plant consisted of bare branches. Some of those had died back so that lifeless tips of branches appeared among the greenery.

The plant had been in place for a few years, and I could not recall its name.

For the past several years, when I added a plant to the garden, I searched the Internet for a photo, a verbal description, cultivation notes, and any other information of interest, and compiled it into a one-page “fact sheet” to be added to my files. Such searches begin with the plant’s botanical name, which is almost always listed on the plant’s tag or nursery container.

As a result, I had a binder of such information for the plants in the Australian bed. Despite this preparation, I could not identify this plant.

After staring at my files for Australian plants, I realized that one fact sheet described this particular plant quite well, but the accompanying photo showed red flowers. The plant in question has white flowers!

Apparently, I had included a photo of a different cultivar of the plant. I learned that the red-flowered cultivar is more widely used than the white-flowered species in my garden. (The ‘Snow White’ cultivar has double, green-centered blooms, but my plant has single white blooms with unremarkable centers.)

I replaced the photo, and was satisfied that the plant is a Tea Tree or Manuka (Leptospermum scoparium), a member of the Myrtle plant family (Myrtaceae) and a native of Australia and New Zealand. The generic name means slender seeds, and the specific name means broom-like.

Tea Tree or Manuka (Leptospermum scoparium)

I then learned that this plant has several desirable characteristics. It is drought-tolerant, fairly slow-growing, appealing to bees and not appealing to deer. It has fragrant, evergreen foliage and a profusion of small flowers that appear in the late spring and summer, and linger into the fall. Its leaves can be brewed into a fine tea and Manuka honey produced by bees from its flowers has medicinal properties.

On the downside, at maturity this plant can reach ten feet tall and wide, making it too large for my Australian bed.

I considered pruning this shrub to manage its size. My Internet research found advice that the Tea Tree could be pruned after flowering to maintain shape and encourage bushier, more floriferous growth. However, pruning should never cut into bare wood “as new growth is unlikely to sprout.”

This reflects the pruning advice for plants that also flower on the previous year’s growth, including Camellias, Rhododendrons, Lavenders, and several others. This is critical information, because hard pruning of the Tea Tree would leave it looking and performing essentially dead.

While a light pruning after pruning would stimulate next spring’s growth at the ends of branches, there is no opportunity to reduce and maintain this sprawling plant to a more compatible size. If had been grown as a hedge or as a backdrop for the garden, it could have had long-term value in the landscape. In its current stage of growth and its present location, however, it will be an increasing problem.

This assessment of a particular plant recalls a basic guideline for landscape planning: always know a plant’s size at maturity before buying and placing it in the garden.

Great satisfaction can result from a well-placed plant. Conversely, removing a healthy plant leads to regret. From a positive perspective, removing the Tea Tree will eliminate conflict with nearby plants and free space for smaller Australian native plants.

WInter Bloomers from Mexico

There’s a lot that I’m thankful for, including a couple fall-season bloomers in my garden.

I have recently mentioned these two plants, which are natives of Mexico, but they are blooming right now and deserving of attention.

The first is the Tree Dahlia, which produces attractive blossoms in November, and also astonishes me each year with its annual growth. The Tree Dahlia (D. Imperialis) originated in the mountains of Mexico and Guatemala. It is an historic favorite of Mexican gardeners, and an ancestor of the garden dahlia, Mexico’s national flower and a current focus of hybridizers.

Tree Dahlia in bloom

Botanists travelling with the Spanish conquistadores discovered the Tree Dahlia and brought it to the Royal Gardens of Madrid by the late 1700s. The genus became popular throughout Europe and was recorded in the United States bas early as 1821.

In one season, a Tree Dahlia with established roots will grow up to twenty feet tall, with clusters of lavender pink blossoms high in the air, to be enjoyed from below. The blossoms are free of fragrance, which is not a problem given their height.

If a Tree Dahlia were to be planted below a deck of just the right height, people could appreciate the blossoms more closely. That would be a fine deck-plant combination.

The magical nature of this plant is its annual cycle. Around March, after it finishes blooming and its leaves have faded, the canes can be cut to about six inches from the ground to stimulate new growth from the roots.

The canes can then be cut into sections and planted to start new plants. Each section should have at least four leaf nodes and still leaking liquid sap. These cuttings are then planted right side up in sandy soil or potting mix and watered from time to time, until they show new green shoots. This plant is not difficult to propagate!

I first encountered the Tree Dahlia several years at a Master Gardener workshop, when someone shared cane sections. I planted those sections at the edge of my garden, in a partially shaded area. They grew quickly.

This plant is available commercially at least occasionally from Annie’s Annuals and Perennials, and few other sources. It’s a good example of a “pass-along plant.”

Given an appropriate site, it is a spectacular seasonal addition to the landscape.

Blossoms of the Daisy Tree

A second favorite plant at this time of the year is another Mexican native, the Daisy Tree (Montanoa Grandiflora).  This is an upright, evergreen shrub that grows up to ten feet tall and wide. It develops large, deeply lobed, rather leathery tropical looking leaves.

In November, it produces clouds of daisy-like flowers, white with yellow centers, with the fragrance of chocolate or freshly baked cookies. After about a month, the blossoms are replaced with long lasting “bouquet-worthy” chartreuse seed heads.

In the early spring, the branches should be cut to the ground to stimulate a new cycle of growth. Like the Tree Dahlia, this plant grows vigorously from its roots to produce a striking new presentation each year.

My first introduction to the Daisy Tree was during a visit to the Esalen Institute on Big Sur, during a stop on a tour hosted by the Pacific Horticultural Society. I was impressed by the plant, and searched diligently for a small plant for my garden. It’s not offered widely, but I found it it eventually at Annie’s Annuals & Perennials.

This is a large shrub, so it works best in the landscape if it’s placed in a space large enough to accommodate its spread, and close enough to a walkway to enjoy its fragrance. While it is evergreen, the recommended practice for rejuvenation pruning means that the garden design should anticipate its periodic absence. When the gardener cuts down the Daisy Tree, he or she might plan to fill the void with wildflowers.

Plants like the Daisy Tree and the Tree Dahlia bring dynamic qualities to the landscape, and welcome gifts to the holiday season. 

Palm Trees of Santa Cruz

While browsing an online update from the San Francisco Botanical Garden, I discovered the Chilean Wine Palm (Jubaea chilensis), which is interesting to me because my garden includes a section for Chilean plants.

Santa Cruz also has at least two Chilean Wine Palms, which is another species with pinnate fronds. A prominent specimen can be seen on the hillside below Mission Santa Cruz, toward the downtown area, close to an Australian Bunya-Bunya tree (Araucaria bidwillii).

A Chilean Wine Palm in Santa Cruz

This tree is unusual because it develops an unusually thick trunk, grows very slowly, and produces sap that can be used to make wine. The tree becomes rather too tall at maturity (eighty feet, potentially) for my garden.

Still, learning about the Chilean Wine Palm enticed me into exploring the world of palm trees. This column provides only a brief introduction to these interesting trees, which are widely used in California’s landscapes.

Palm trees are members of the botanical family Arecaceae, with some 2,600 species. Several different plants are included in this family; only the tree-form plants are called palm trees.

Types of palm trees can be grouped by the form of their leaves, which are called fronds.

  • Palmate leaves are characteristic of fan palms. The leaf parts radiate outward from a central area.
  • Pinnate, which is the most leaf form, resembles a feather with a central rib, with the ends divided into individual leaflets.
  • Bipinnate fronds resemble a fish tail.
  • Entire fronds, which are the least common form, resemble pinnate leaves but are not divided at their ends into individual sections.

There are quite a few palm trees in Santa Cruz. If you deliberately look for them while driving about, you will notice many trees and several different varieties. Some of the more recognizable varieties growing locally are the following:

Mexican Fan Palms (Washintonia fillifera) along the Santa Cru Boardwalk

Queen Palm (Syagrus romanzoffiana). Several of these very popular trees have been planted fairly recently, particularly near the Wharf/Boardwalk area. They line the main street of Capitola Village. Pinnate fronds.

Mexican Fan Palm (Washingtonia robusta). This is the tree along Beach Street. In 1962, former Boardwalk president Laurence Canfield planted 42 trees on this street and donated them to the City of Santa Cruz. These trees can grow 100 feet tall and live for 100 to 150 years. Palmate fronds.

California Fan Palm (Washingtonia fillifera). These are the only palms native to the west. Compared with the Mexican Fan Palm they grow shorter (about sixty feel tall) and develop thicker trunks. A good specimen can be seen on Morrissey Boulevard, near Fairmount Street. Palmate fronds.

Canary Island Date Palm (Phoenix canariensis). These trees can grow to sixty feet tall, with canopies thirty feet across. A fine specimen is in the garden of the Santa Cruz City Hall, reportedly planted by birds many years ago. Also, a pair of these trees is at the Darling House, on West Cliff Drive.  Pinnate fronds.

For an extensive catalog of local palm trees, with photos and descriptions, visit Peter Shaw’s blog, http://treesofsantacruzcounty.blogspot.com. Dr. Shaw is Horticulture Department Chair at Cabrillo College, and a self-confessed tree guy. His blog also includes information on a wide range of trees in addition to palm trees that can be found in Santa Cruz County.

The large family of palm trees include a great diversity of shapes and sizes, so one or more of these plants might bring a welcome look to your landscape. In any event, you can appreciate these icons of tropical environments in our community.

The Striking Castor Bean

Of the many plants in my garden, one that I particularly appreciate is the Castor Bean, because of its several interesting characteristics.

This plant, known botanically as Ricinus communis, is a member of the very large Spurge family (Euphorbiaceae). It grows as a tree that can exceed thirty feet in height in nature, but generally reaches only about ten feet high in gardens. It is native to the Mediterranean Basin, East Africa, and India, and has become widespread in tropical regions. It is widely grown in southern California gardens, and it also grows well in the Monterey Bay area.

The form and color of its leaves are its most striking characteristics. While there is considerable variation in the leaf color, the most common variety begins with dark green and develops into a dark and glossy reddish-purple. This color can provide a dramatic ornamental value to the landscape.

The leaves are palmate, i.e., shaped like a maple leaf, but with five to twelve deep lobes with coarsely toothed segments. From August to November, it produces both male and female greenish-yellow flowers that lack petals. The female flowers have red stigmas, producing a showy appearance. The flowers are followed by an abundance of reddish-brown seed capsules.

Castor bean leaves and seeds

All parts of the plant are poisonous, and the seeds are strongly poisonous. They contain the highly toxic substance, ricin, which has become notorious in connection with international terrorist actions.

Castor oil can be extracted from the seeds, and with proper care can be made poison-free. The oil has several medicinal applications, including as an unpleasant purgative, which was more popular in my youth than it is today. The oil also has commercial applications, e.g., in hydraulic brake fluids, laundry detergents, and paints and varnishes.

In the garden, this poisonous plant must be managed with care, particularly if young persons are present on occasion. While children are unlikely to nibble the leaves, twigs, or flowers of any plant, they might find the seeds of the castor bean to be appealing. One seed could kill a small child! Certainly, children should be educated to enjoy but not eat plants in the garden, unless specifically invited.

Gardeners likely to have children roaming about in the garden unattended might well decide that plants other than the castor bean could provide an interesting feature in the landscape. 

Another characteristic of this plant is its vigorous growth habit. It has created more rapidly growing seedlings than any other plant in my garden. It would not take long to have many castor beans in one’s landscape.  In fact, it is considered an invasive plant anywhere in California. Its invasiveness is based more on its enthusiastic spread than a capability to out-compete other plants.

Recently, when I pruned back some branches that were encroaching on a walkway, the work caused several seeds to drop, and they soon sprouted to create a carpet of seedlings.

I have found the castor bean plant to be fairly manageable, because the seedlings, although many in number, are readily recognizable and easily pulled. The seedlings are probably easy to transplant, but I have not potted up any to share at the local garden exchange because of their combination of prolific propagation and poisonousness.

Many garden plants are well behaved and uniquely attractive, but others stand out in one way or another. The castor bean is an exceptional performer through its gorgeous leaf color, vigorous self-propagation, and the deserved reputation as the world’s most poisonous plant. If you can handle it, you too might enjoy having this plant in your garden. (Let me know if you’d like a seedling!)

Protecting Against Garden Pests

Gardening friends have commented on this season’s unusual uptick in pesky four-legged vertebrates, inspiring this column’s exploration of ways to protect our gardens from these pests.

Our reference to “four-legged vertebrates” narrows the discussion, leaving out the “two-legged” varieties: unauthorized snippers of cuttings, midnight diggers of special plants, clumsy browsers of garden beds, and rambunctious kids.

This exclusion extends to birds (which we might address in the future), bats, and also snakes, which have vertebrae but no legs, and some of which are not pests but assets in the garden.

We also exclude the non-vertebrates, an enormous number of wildlife creatures ranging from small to very, very small. That group is mostly beneficial, although with a good number of bad actors. That category is worth more attention than could fit into a newspaper column.

So, when considering four-legged vertebrate pests, we begin with habitat issues. We can proceed best when we acknowledge that our historically recent gardens are in places where they have lived during many generations. We are intruding into, or reducing, their habitats.

We can’t easily eliminate that interface, so we should try to live harmoniously.

Wild animals prefer to stay away from people, and smart people usually don’t want to interact with wildlife, so both parties are inclined toward peaceful co-existence. Gardeners can support that relationship in two ways without being hostile.

  • Animals are always looking for food, so this means we should not provide food deliberately, or accidentally, e.g., leaving pet food outdoors unattended, leaving kitchen waste in uncovered compost or trash containers, or not harvesting ripe fruit or vegetables. (I think animals are raiding the dropped apples in my garden!)
  • Animals also are always looking for safe spaces to sleep or raise their young. Attractive spaces might be under your house or deck, so close off such spaces with quarter-inch mesh hardware cloth or other materials.

At another level, limit wildlife access to edible plants in your garden. This can be accomplished with fencing that is appropriate for particular pests: high for deer, lower and underground for several smaller raiders, including gophers. Lining the bottom of garden beds with wire mesh or installing gopher baskets can be successful in discouraging gophers. These materials are available in garden centers or on the Internet (see, for example, the website for Gophers Limited.)

A more aggressive approach to limiting access to plants is trapping. Some traps are designed to kill, and others are designed to detain.

Many gardeners are ready and willing to dispatch certain rodent pests, including mice, rats and gophers. Gardeners often regard other rodent pests (squirrels, chipmunks, and porcupines and rodent-related rabbits) as cute and seem them as candidates for release to “somewhere else.” We also would prefer to relocate some other four-legged vertebrate pests, notably raccoons and opossums.

Some people think trapping and relocating a trapped animal pest into nature would be illegal. Our search of federal, state and local government codes revealed a humane requirement to free an animal from a trap within a day’s time, but did not discover a prohibition against relocation. A ban against relocation appears to be an urban myth.

Still, both the Audubon Society and the Humane Society argue that relocation is not a solution to problems with garden pests. Pointing to the territorial habits of wildlife, these groups advise that relocating an animal (a) simply invites another animal to move in its territory, (b) requires the relocated animal to fight the owner the new territory (this could be fatal for a juvenile, or a mother of young animals), or (c) possibly exports disease into the new territory.

These groups basically dislike trapping, and recommend either not attracting wildlife into gardens, or discouraging them with fencing, as suggested above.

Another strategy for dealing with these pests involves using organic fragrances or tastes that animals dislike. We invite interested readers to seek ideas along these lines on the Internet  (search for “animal repellents”).

Then, there are various non-lethal strategies that one might explore, including filling gopher tunnels with water or low levels of carbon dioxide, electrifying fences, making audible or inaudible noises, and other ideas. New ideas pop up often but can be expensive, time-consuming, and of questionable effectiveness.

The final animal control strategy we will mention is the use of poisons. Don’t use them! Poisons can harm pets and children, providing enough reason to avoid them.

Besides, we should treat humanely the animals that share our gardens, even when they eat our plants.

Navigating a Garden Exchange

Tomorrow, the Santa Cruz Garden Exchange will have its last session for the season. The Exchange convened monthly during this year, providing opportunities for gardeners to share lots of surplus plants, plus some fruits, vegetables and garden pots.

Garden exchanges are a fine tradition for gardeners who find they have more plants than they want or need, don’t want to open a mini-nursery business, and can’t bear to discard healthy specimens.

The reciprocal benefit flows to other gardeners who enjoy receiving free plants that thrive in the local climate, and broadening their gardening experience with varieties they might not have encountered previously.

Some participants fill both roles, and can’t decide whether it’s better to give than to receive, or the other way around.

In this column, we explore the botanical context of the traditional garden exchange, where one might encounter many different plants.

Rarities

There are around 400,000 species of flowering plants (angiosperms), according to a team of botanists from around the world, including leaders from the Royal Botanic Gardens herbarium at Kew in London, and the Missouri Botanical Garden in St. Louis. A good number of these plants are considered rare, but that’s a subjectively defined category, and there are almost as many lists as gardeners. To check out the range of nominees, search the Internet for “rare plants.”

Plants are considered rare for various reasons: not yet discovered in the wild; discovered but not distributed by commercial nurseries; not garden-worthy (according to some arbitrary definitions); difficult to grow (this depends a lot on location); endangered as a result of human action, e.g., habitat loss.

Some gardeners seek rare plants for bragging rights or cultivation challenges.

Unfamiliar or Unusual

This category relates to the individual gardeners: what is unusual to one might be a favorite to another. This past week, I attended an expert presentation on Ariocarpus, which is a small genus of succulent, subtropical plants in the cactus family (Cactaceae). They grow in limestone hills in the south of Texas and the north of Mexico. These plants were certainly new to me, but a longstanding interest to the speaker and a few other members of the Monterey Bay Area Cactus & Succulent Society. We all learned these unusual plants are actually easy to grow when given acidic water.

The challenge of cultivating other unusual plants generally involves providing their native conditions. For example, I have been fascinated by Brazil’s giant rhubarb (Gunnera manicata), which has enormous leaves, and wanted to include it in my garden, but this is a plant that requires a lot of water. A local friend is growing it successfully, but he has an on-site water source.

Some mail-order nurseries offer unusual varieties, either as seeds or small plants, so adventurous gardeners will have little difficulty in finding something different. They might be pricey, but that’s part of the enterprise.

Familiar

We find this category of plants in local garden centers and most mail-order catalogs. We need not dwell on this category here, except to acknowledge that it represents the mainstay of residential gardens.

Pass-along Plants

These are the desirable plants often found in traditional garden exchanges. They are garden-worthy and typically very easily grown.

We could include a long list of plants in this category. Here is a typical list of pass-along plants:

  • Daffodil
  • Spider lily
  • Canna
  • Daylily
  • Crinum
  • Iris
  • Camellia
  • Gardenia
  • Ginger Lily
A tall bearded variety of iris, a popular pass-along plants, especially in the fall,
when gardeners dig and divide their iris rhizomes.

Invasives

Our last category to consider consists of the overly zealous propagators. They are sometimes called “vigorous spreaders,” a polite term for plants that will take over your garden, when given a chance.  Many plants belong in this category, and they might show up in a garden exchange, so be on your guard. I once brought home an attractive succulent plant identified as a Bryophyllum. Something new! When I searched for it on the Internet, however, I discovered that its common name is “Mother of Thousands,” and a closely related plant is called “Mother of Millions.” I did not add that plant to my garden.

The Santa Cruz Garden Exchange will occur at 8:00 a.m., Saturday, October 27, 2018, at the Live Oak Grange Hall, 1900 17th Ave. Santa Cruz. The available plants (all free) will include a good supply of high-quality iris rhizomes, to be planted soon so they could establish roots during the coming rainy season. This is the last opportunity this season to participate in this great tradition for home gardeners. Arrive early!