Social Distance XVI – Garden Paths

This column continues explorations of three kinds of gardening activities that can respond to our creative energies, support healthful exercise, and improve the quality and enjoyment of our living environments.

Care for Your Garden

We recently touched on the Big Three of Weeding: pulling, solarizing and mulching. In this column, we survey ways to minimize weed growth on garden paths.

Some gardens consist of lawns with planted garden beds that either around or within the grassy area. In landscapes with large garden beds the lawn might take the form of narrow paths between the planted areas. In either case, managing weed growth in lawns requires supporting vigorous growth of the grass (good for the environment) or applying a broadleaf weed killer (bad for the environment).

The following notes focus on non-grassy garden paths.

The most basic garden path is bare soil, compacted by foot traffic. Such areas still can foster weed growth, although a layer of organic mulch could help to discourage weed rooting.

The next level of limiting weed growth is to cover basic paths with decomposed granite (“DG”), which is coarser than sand, with angular grains that can be tamped down to form a firm surface. Landscape fabric might be placed on the path below the DG installation.

A three-inch deep layer of DG provides an inexpensive path that is not hospitable to weed growth but weeds eventually will establish roots in the DG and their removal become a time-consuming maintenance task. While landscape fabric discourages weed growth from below, the weeds begin with seeds that winds and birds bring to the path’s surface.

As the DG path becomes weedy, practical weed management could be accomplished with occasional spraying of 20% or 30% vinegar. This organic treatment requires careful handling to protect desirable plants and nearby gardeners from this harsh chemical.

Some advisers recommend household vinegar (5%) mixed with table salt plus a small quantity of liquid detergent as a surfactant. Spraying with this solution will trouble weaker weeds but doesn’t really get the job done.

A DG path can be protected from weed growth with the use of a stabilizer that is added to the DG before installation. This method yields an attractive, durable, and permeable surface that is less expensive than concrete. Stabilized DG is best installed over a bed of crushed gravel. For one example of this product, see

The most stable and durable type of DG uses natural resign mixed in with the decomposed granite aggregate. This creates an asphalt-like material, but with a more natural look.

Then, we have a variety of hardscape paths. These include natural flagstones, cut stone slabs, common bricks, and concrete pavers. These materials should be installed over a bed of crushed gravel for stability plus a layer of sand for adjustment to a level surface. The gaps between the paving materials can be filled with sand, but such gaps eventually will harbor weed seeds and result in a weeding task.

A better method for filling gaps between paving materials is the use of polymeric sand, which is available from landscape suppliers. This filler is a mixture of fine sands and polymers that, when mixed with water, form a binding agent that locks the sand particles together and results in a uniform, durable surface.

Concrete provides ultimate and most costly protection from weed growth on garden paths. This approach includes installing concrete under and between the paving materials or creating a solid path by pouring concrete between forms. In either approach, a bed of crushed gravel is needed in for stability.

Advance Your Gardening Knowledge

As always, useful information on each of these methods for weed control on garden paths can be found by searching the Internet for the respective keywords. A search of YouTube also will lead to video clips that demonstrate the methods.

Enrich Your Gardening Days

The UCSC Arboretum has reopened, following a closure period in response to the Covid-19 pandemic. This extraordinary facility offers a pleasant and completely safe opportunity to  enjoy unique garden vistas and gather inspiration for your own gardening ventures.

The Wollemi Pine (Wollemia nobilis) had been known only from fossils up to 200 million years old, but was discovered in Australia in 1994 and is being grown again in botanical gardens.

Erica mammosa ‘Ninepin’. The species name for this South African heath plant refers to the udder-like shape of the flowers.
The Spider Flower (Grevillea)grows in a wide range of sizes

Photographs with this column have been created by Bill Bishoff, the Arboretum’s volunteer photographer, as samples of the many plants that are in bloom at the “Arb” right now.

The Arboretum’s hours are from 9:00 to 5:00 every day. Admission is $5 for adults, $2 for children, and free for volunteers and members. When visiting, practice social distancing, wear a mask and bring your own drinking water.

For driving directions and information about being an Arboretum member or volunteer, visit The website also has links to purchase Arboretum plants online for curbside pick-up.

Keep your emotions positive and your viruses negative and enjoy your garden.

UCSC Arboretum’s South African Garden

Here’s a fascinating advancement in local garden development: the Arboretum & Botanic Garden at the University of California, Santa Cruz has launched a complete renovation of its South Africa Garden. Over at least the next seven months, this project will include restoring the garden’s unique plantings, recovering lost rare specimens, and adding new plants for display.

The South Africa collection was established early in the Arboretum’s history, as long ago as 1965. It soon emerged as one of the Arboretum’s principal collections, along with the California and Australia Gardens.

The South Africa Garden has always been open for visitors, but when its curator retired some ten years ago, during a period when the Arboretum was going through administrative changes, the growth of this collection stalled. In public gardens, collection development is a continuing, never finished process, but this work requires leadership, vision, energy and critical resources.

In mid-2016, Martin Quigley joined the Arboretum as its Executive Director, and soon began planning to reactivate the South Africa garden. The new plan includes the installation of four new specialty gardens, each of which highlights important and very interesting plant groups.  These specialty gardens will serve as focal points within the overall collection of exceptional plants of South Africa

A Succulent Rock Garden, featuring the juicy Aloes, gnarly Euphorbias, and other fantastic succulents. This installation will constitute a South African version of the dramatic and very popular rock garden in the Arboretum’s Australia Garden. South Africa is the native home of about 50% of the world’s succulent plants, which have in recent years become very popular in private gardens. The Arboretum’s existing Succulent Garden focuses on succulent plants from the coastal areas of Mexico and California, so the establishment of the Succulent Rock Garden will draw attention to that category of plants that are native to South Africa.

A South African Bulb Garden will be encircled by bright and vibrant amaryllids, and highlighted by the full spectrum of fire-adapted geophytes in mass bloom! The “amaryllids,” which we assume refers to South African members of the Amaryllis family, includes genera that some Monterey Bay area gardeners already know and treasure: , e.g., Amaryllis, Clivia, Crinum, Nerine, and others. South Africa’s Cape Region is also the home of 2,100 species of geophytes, includes some that only flower or germinate after burning. The fire-adapted geophytes occur within six plant families; we will have to see which species the Arboretum selects for this colorful Bulb Garden.

A Maze Garden, in which 6- to 8-foot-tall Restio species form a traditional labyrinth. Restios are perennial rush-like flowering plants native to South Africa. This unique feature promises an intriguing experience for garden visitors of all ages.

A Grove of Silver Trees, growing among colorful waves of heathers. Silver Trees (Leucadendron argenteum) are striking evergreen trees with silky leaves that have a distinct silvery sheen produced by dense velvety hairs. These trees are short-lived, and are now a rare and endangered species in South Africa. For many years, the Arboretum has grown Silver Trees in the South Africa Garden. A new grove of these extraordinary trees will present a magical environment. It could be a very appealing site for Weddings in the Arb!

Silver Tree (Leucodendron argenta), Photo by Bill Bishoff, provided by UCSC Arboretum

The Arboretum hosted a special event to launch this renovation project. The South Africa Garden Party happened from 5:00 – 7:00 p.m. on UCSC’s Giving Day, Wednesday, February 27th, in the Arboretum’s Hort II Building. Attendees heard the Arboretum director’s inspiration and vision for the project. Alice in Wonderland costumes and games sparked their creative, whimsical side. Some attendees even came home with a wild hat.

Donations will go towards the education of twenty UCSC students in horticulture, plant biodiversity, and the practice of public garden management. Their work will advance the completion of this important project.

In September 2019 donors will be invited to a special reception showcasing the artfully and expertly constructed garden displays, along with an insider’s peek at how it all came together.

This extraordinary project will revitalize a significant horticultural resource for the Monterey Bay area and all of California.

Visit Public Gardens on Summer Vacation

We have now officially entered the summer season, which is an excellent time for gardening and traveling. One way to combine those activities is to visit a public garden.

The Internet harbors many “Top Ten” lists so my own travels began with a search for “best U.S. public gardens.” If you conduct your own search using these or similar words you will encounter a trove of possible destinations, including six lists that I explored. Here are some impressions.

First, there are many places that qualify as public gardens. National Public Gardens Day happened on May 11th, when 150 botanical gardens and arboreta within the United States offered free admission. These included most of the principal sites, but there are many more to discover.

Then, the Internet’s lists of Top Ten gardens are all strikingly different. While a few gardens appear in more than one list, it’s evident that there are diverse ideas of which gardens deserve to be called “best.” The direct experiences of the list-writers undoubtedly influence their selections. One exception is the USA Today’s list, which is based upon the votes of garden visitors.

The most popular gardens on these lists are Longwood Gardens, Kennett Square, PA; New York Public Garden, New York City, NY; and Fairchild Tropical Botanic Garden, Miami, FL.

The most popular gardens in the western part of the nation (which might be more convenient for Monterey Bay residents to visit) include The Bloedel Reserve, Bainbridge Island, WA; Washington Park Arboretum, Seattle, WA; Portland Japanese Garden, Portland, OR; International Rose Test Garden, Portland, OR; Mendocino Coast Botanical Gardens, Mendocino, CA; San Francisco Botanical Garden, San Francisco, CA; Lotusland, Montecito, CA; Huntington Botanic Gardens, San Marino, CA; and Desert Botanical Gardens, Phoenix, AZ.

To be accurate, the western U.S. includes these rather less accessible gardens of the National Tropical Botanical Garden, which includes McBryde Garden, Allerton Garden, Limahuli Garden and Preserve (all on Kaua’I Island, HI) and Kahanu Garden (Maui Island, HI).

Noteworthy public gardens that are closest to the Monterey Bay area (in addition to the SF Botanical Garden) include the Arboretum and Botanic Garden at the University of California, Santa Cruz; Hakone Estate and Gardens, Saratoga, CA; University of California Botanical Gardens, Berkeley, CA; and Bancroft Garden & Nursery, Walnut Creek, CA.

For more information on any of these gardens, use their name to search the Internet.

The many available gardens could not all be mentioned here, and any omissions are not intended as downgrades. The reality is that each public garden offers a unique combination of plants and a setting that might appeal differently for the individual visitor, so a realistic strategy for the adventuresome gardener is to visit as many public gardens as may be convenient and practical and discover which is most satisfying. This could be a rewarding exploration that you might begin during this year’s summer season.