“Varmints” in the Garden!

By Tamara Blett

Do gophers and other burrowing critters in your garden make you want to play “whack a mole”? If so, you’re not alone, the digging rodents are known to create havoc in landscapes; eating plant bulbs, roots, fruit and vegetation, and turning yards into surfaces resembling swiss cheese, as they tunnel their way through your yard and through our lovely planting areas here at the SLO Botanical Gardens. The burrowing rodents in the Central Coast are most commonly either California ground squirrels or pocket gophers. Both are common in residential settings and here at the SLO Botanical Gardens, so let’s take a closer look at these critters and see what they are all about.

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Pocket gophers are named for their cheek pouches, used in transporting food to their burrows.  Gophers are fossorial, meaning that they eat, sleep and breed underground, and are rarely seen aboveground. They are usually brown with tiny ears, long whiskers, and a short, thick, almost hairless tail. Gophers are herbivores who mostly eat the underground parts of plants (roots and tubers) but occasionally surface for a bite (or more!) of greenery, sometimes pulling whole plants back into their burrows, for a later snack. The presence of gophers can be identified in the garden by large mounds of soil next to an exit tunnel.

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The California ground squirrel is found throughout the state and thrives where winters are mild. Ground squirrels are a mottled grey and brown on top, with a lighter color on their bellies, a white eye ring, and bushy tails.  They are easy to identify because they forage above ground but will retreat to their burrows when frightened (distinct from tree squirrels, who instead climb a tree when startled, and never use burrows). Signs that grounds squirrels are at work nearby include many adjacent holes, smooth little paths in and around the tunnels, or loose plant material from vegetation feeding.

Do gophers and ground squirrels carry diseases? Well, as with many other animals such as wood rats, prairie dogs, chipmunks, mice and rabbits, gophers and ground squirrels can be infested with plague carrying fleas. This is relatively rare for gophers, but occasionally possible for ground squirrels because they live in large colonies, where diseases can be transmitted quickly. Burrowing rodents can also spread other diseases, so caution (and gloves) should be used when near animal burrows, and unusual number of dead rodents should be reported to public health officials.

Here at the Botanical Gardens, we discourage gophers and other burrowing animals in our planting areas by encouraging natural predators such as owls and hawks. The SLOBG has installed many owl houses and hawk nesting platforms around the perimeter of the gardens to provide free lodging for any birds willing to stand guard duty and enjoy free meals. These sharp-eyed raptors are even better at rodent control than humans could be, because they are on duty 24/7 and have keen sight and hearing designed just for locating prey. As a last resort, if the animal burrows become too dense, or enter vulnerable planting beds in the gardens, we use “smoke bombs” (administered by trained applicators) for below ground treatment of the critters.

For dealing with burrowing animals at home, we recommend that you: (1) Identify which type of critters are present; (2) Locate “fresh” areas of activity, by flattening out soils mounds with a shovel, and only treating the area if new mounds appear (also cover up old, inactive holes) and;  (3) Visit your local nursery or ranch supply store to ask what pest control products and deterrents work in your area. The options will be in one of two categories: non-lethal (discourage the critters from visiting specific garden areas) or lethal.  Non-lethal options may include planting new perennials and shrubs with “root baskets” surrounding the below-ground portions of the plant; broadcasting castor oil pellets or liquid spray (a natural repellent) around active burrows and throughout planting areas; or ultrasonic sound deterrents (sometimes effective for small areas). Lethal options may be desired for large acreages, or severe, recurrent damage to property or landscapes. These include setting traps or using smoke bombs or poisons, and all should be used with caution or under the guidance of a licensed professional.  

If you can’t beat them…. then try to appreciate the burrowing mammals for their place in the environment. Gophers and ground squirrels help add nutrients to soils; decomposition of the plant material underground, along with rodent poop can produce deep fertilization of soils. The burrows and furrows made by the tunnels provide soil aeration which can capture rainfall that might otherwise runoff and be lost. And gophers also serve as food for our owls and hawks… nature’s natural “varmint” control.

Science in the Gardens: It’s About Time

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The drive to understand our world is one of the reasons why science is important; the delicate dance of air, water, soils, plants and animals on this planet supports life--- both human life and everything else from earthworms to eagles. Learning how this balance works and why is fascinating, and it can help us make wise choices which support the things that people need from the earth; like fresh water, healthy soils, prolific crops, and controlled insect and disease outbreaks.

Understanding our world begins with asking “why”; and farmers, gardeners, scientists and schoolchildren have often wondered why and how plants, insects and birds behave differently from year to year. What causes cherry trees to bloom later some years? When will the monarch butterflies arrive? Does spring really seem to be arriving earlier than it did when I was a child? The answers to these questions begin with timing; nature keeps a hidden calendar whose secrets can be unlocked with a little detective work.

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Here at the San Luis Obispo Botanical Gardens a fascinating science project has been ongoing since 2012; where five of the Garden’s plants are being tracked by a long-term SLOBG volunteer. Each week, for the California buckeye (Aesculus californica), California wild rose (Rosa californica), California live oak (Quercus agrifolia), California poppy (Eschscholzia californica), and Chamise (Adenostoma fasciculatum); our volunteer takes careful notes on data sheets in a fat notebook containing six years of carefully collected information. Observations are made for when bud and leaf growth first begin; and when plants flower, release pollen, and produce fruit. Coyotebrush (Baccharis pilularis) and Eastern Mojave Buckwheat (Eriogonum fasciculatum) were initially included in the SLO-BG monitoring study, but flunked the class when they died off after a few years. Temperature and precipitation data are also noted to see how the plants respond to seasonal and annual changes.

All weekly notes and data are submitted on-line to the “Nature’s Notebook” at the National Phenology Network (https://www.usanpn.org/). This program is a nationwide effort to track nature’s calendar and determine how and when cycles change over time.  The National Phenology Network (NPN) is one of the longest running and most comprehensive citizen science efforts in the country, recently reaching a milestone 15 million records submitted by citizen scientists, government agencies, non-profit groups, educators, and students of all ages. After completing training, anyone can become a “citizen scientist” submitting data on key plant species to the NPN. The SLOBG is one of over 3200 monitoring sites in California alone, which submits seasonal cycle information on plants, insects and/or animals to the NPN.

The results can be used nationwide to help recognize and document nature’s cycles affecting people and the environment; such as developing a better understanding of when pollen season is likely to affect allergies; and helping farmers and gardeners track plant and insect development to decide when to apply fertilizers and pesticides. The information is also used to follow the effects of climate change on plant development to see whether long-term seasonal shifts in weather patterns are affecting plants; and what these changes will mean for the animals and insects who depend on them for food, shelter or nesting. For example, NPN data has been used to show that across the US, the beginning of spring (onset of new leaves and buds) is occurring earlier now than 95% of historical conditions during the past century (https://www.nps.gov/subjects/climatechange/upload/2016-10-26-NPS-Phen-Project-Brief.pdf).  This year, a premature spring is on the way once again, as NPN data from the past few weeks shows that spring is indeed arriving earlier across much of California, as of early 2019.

Our phenology tracking volunteer has discovered that observing the same plants over time has been a rewarding process, because looking at all phases of the plants more thoroughly enhances her powers of observation. Over time, the seasonal trials, tribulations, successes and failures of each plant are revealed to tell stories which can be shared with everyone across the world.  While many more years of patient plant tracking at the SLOBG will be needed to see whether our plants are responding to a changing climate, the information collected from this project gives us a little better understanding on the fascinating world of plants, and how they experience their world both individually and as a whole.

Let’s Go to South Africa (in the Botanical Gardens)

South African Succulents

By Tamara Blett


Where can you find rugged Mediterranean plants, a world-famous wine region, scenic train routes, rugged rocky coastlines, and abundant birds and wildlife? The answer is BOTH the Central Coast of California and the southern-most country on the continent of Africa; South Africa. The San Luis Obispo Botanical Gardens specializes in plants native to the world’s five Mediterranean regions, including the South African Mediterranean area. You don’t have to travel on a long plane ride to view some of the spectacular plant life native to the African continent, just pack your camera, and walking shoes and take a short trip to the SLOBG.

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South African native plants have relevance for us here in the Central Coast, because they can survive and thrive in our local Mediterranean environment, increasing the repertoire of plants available to both the SLOBG and to gardeners at home. South African succulents are low maintenance, drought tolerant, fire resistant, and help prevent slope erosion. But perhaps their most appealing characteristic for gardeners is that many of these plants are winter bloomers, providing a welcome splash of color in January and February.  Maintaining a good selection of South African plants here at the SLOBG or at home is one of the best strategies for ensuring year-round blooms in a diverse and bountiful garden. Hummingbirds also visit the tempting flowers from the South African natives at the Botanical Gardens all winter long, and compete with each other for the best access to their sweet nectar.

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Most people are familiar with succulents as plants that store water in their stems, roots and leaves, making them feel fleshy or juicy. A common species of succulent plant contains the aloes.  The “juice” or sap of the aloe plant is well known as a remedy for scrapes and minor burns, but use caution (!) not all aloes are created equal, and some of them are NOT recommended for those uses. The two types of aloe plants most commonly used for medicinal or cosmetic purposes are Aloe vera and Aloe ferox.  Aloe vera has long been an ingredient in lotions and gels intended to soothe minor burns and moisturize skin, and Aloe ferox is valued as a commercial ingredient in many cosmetic products.

You’re invited to join us here at the Botanical Gardens on Saturday January 12, 2019 from 1-2 pm for a fascinating talk about South African succulent plants, including the aloes, presented by John Trager, the curator of the world-famous Huntington Desert Garden in Southern California.

There is no need to pack your suitcase for international travel just yet, the SLO Botanical Gardens has a little sample of South Africa just waiting for you to come and experience.

Does Nature Flirt?

Plant Pollinators in Action

by Tamara Blett

Plants don’t have on-line dating options for attracting the opposite sex, so they’ve evolved a wild and diverse bunch of strategies for ensuring the next generation of plants. Most plants reproduce by attracting pollinators to their flowers, with unique shapes, smells and colors to guide or tempt them into landing and exploring in just the right place to help bring together the pollen (from the male part of the plant), with the ovule (the female part of the plant). The pollinators benefit by getting a reward of food (nectar or pollen) or place to lay their eggs, and the plants benefit by producing fertilized seeds or fruit to continue their life-cycle into the future.

Here at the San Luis Obispo Botanical Garden we have some fascinating examples of the tricks and strategies plants have evolved to propagate themselves with the help of birds and insects.  Flower position is the first one; horizontal flowers tend to attract birds, and flowers that face upward often attract butterflies. One of our favorite butterfly attractors here at the Garden is the common yarrow (Achillea millefolium), which has white flowers in flat clusters. Color is crucial; birds notice red flowers more easily than other colors, while honey bees are color blind to red, but can see purple, yellow and white flowers. Some attractive flowering plants that birds love to visit here, are the hummingbird flower (Epilobium canum) and the island bush snapdragon (Gambelia speciosa).

Photo by Carolin Reuter

Photo by Carolin Reuter

Plants also release scents to draw in pollinators; sweet smells to attract bees, strong smells to bring in moths, and fruity smells to tempt beetles. The spice bush (Calycanthus occidentalis) near the entrance to the Garden has reddish flowers which are pollinated by a 3mm long beetle. The plant lures the beetle with a strong odor, but once the insect enters the flowers it is trapped by stiff downward pointing bristles and it has been fooled, no nectar is there! The beetle may remain stuck in the flower for up to two days, until the flower releases enough pollen to thoroughly dust the body of the insect. At that point the flower’s petals open wide and the pollen-carrying beetle is released.

Photo by Carolin Reuter

Photo by Carolin Reuter

Plants may also help the pollinators find the payoff of nectar, by showing them where to land on the flower and giving them directions to the good stuff. “Nectar guides” are lines or patterns on the flower petals that say to an insect “follow me to your nectar reward!”  Research has shown that having nectar guides can be beneficial to the plant as well, as the pattern guides the pollinator on a route which is most likely to result in coating the insect with pollen, resulting in greater chances for fertilization of other plants. Peruvian lilies (Alstromeria hybrid) are beautiful, large, pink and yellow flowers that grow in our botanical gardens. If you look closely at the petals, you will notice brown spots and lines which serve as nectar guides for bees on this species.

The Garden Shop has a wide selection of pollinator friendly plants available for sale, so stop by and pick some up for your own home’s landscaping, or come and stroll the paths of the botanical gardens to see plant flirts in action!