When to Plant Flowering Plants

The gardener planning to expand or renew a collection of flowering plants should know the preferred times to buy and install.

For perennials, a good time to plant is during the early part of the rainy season. This schedule relies on the rain to water the plants while they establish roots before flowering in the spring. In the Monterey Bay area, the rainy season begins typically in mid-October or early November and continues through March, with the greatest rainfall in January.

For some popular flowering plants, the ideal planting times relate to dormancy periods. A rule of thumb is to buy and install such plants when they are on sale by gardening groups.

The Monterey Bay Iris Society holds an early sale of tall bearded iris rhizomes at The Garden Faire, on the first Saturday of the summer season. This year, the Faire will be on June 22nd. The Society has two larger sales in the first half of August. The Society has its show early in May, when gardeners can see tall bearded irises in bloom.

Other kinds of irises have annual cycles that differ from the tall bearded irises. The rhizomes of beardless irises, e.g., Japanese, Louisiana, Siberian and Spuria irises, are planted in early October. Divisions of California native irises are planted around the end of August.

The Monterey Bay Iris Society does not offer beardless iris rhizomes or California native iris divisions at its sales, but some garden centers offer these plants. Also, the Society for Pacific Coast Native Irises sells seeds during the fall of each year; in 2012, the last day to order seeds was December 31st. Seeds can be planted during the winter months, with blooms expected early in April.

Another local example is the Monterey Bay Dahlia Society, which has its primary sale in early April. The society’s annual show is held typically at the end of August.

Roses are most often sold during their dormancy as bare root plants from late fall through the winter months. Garden centers and mail order nurseries are the principal sources. The Monterey Bay Rose Society does not sell rose plants, but it has an annual show in May, where gardeners can see roses that grow well in the Monterey Bay area.

Gardeners often buy annuals in the spring when they are in bloom. While it’s helpful to see the bloom before buying, the plant might be peaking in the garden center and ready to decline in the garden. A better plan is to buy six-packs of annuals earlier in the spring, and let them bloom in the garden.

Visit ongardening.com for more ideas about planting times. Be a smart plant buyer, and enjoy your garden!


For planning a vegetable garden, a helpful resource is the Spring Garden Planting Guide, published by Mother Earth magazine. It’s available online. Click here for the Guide and a Spring Garden Worksheet.

Attract Pollinators to Your Garden

Synthetic chemicals have a variety of garden uses: adding nutrients to the soil (or directly to plants), discouraging/killing harmful insects and other small pests, and protecting plants from viruses, fungi and other scourges.

These benefits, however, come with downsides, including destroying microorganisms in the soil and beneficial insects, accumulating salts in the soil, and harming (or worse) pets and gardeners themselves. And there’s more, too much to review in this column.

Our present focus is on the harm that synthetic chemicals bring to insect pollinators: honeybees, native bees (which are different) and butterflies. Concerned scientists and citizen scientists have recorded significant population declines among these pollinators, and have pointed to pesticides as the likely cause of these declines.

Our gardens need these pollinators. They are essential in sexual reproduction of plants, including the development of fruits, vegetables and berries, all of which bear seeds, and both natural and human-directed hybridization of plants.

There are also asexual forms of plant reproduction, to be sure, but we’re concerned here with the pollinators.

The first priority in attracting pollinators to your garden is to adopt organic gardening methods, i.e., no synthetic chemicals. Safe organic products are available to address any gardening need, and integrated pest management (IPM) strategies work better and cheaper in the long run than the quick fixes of synthetic chemicals.

The next important priority is to plant more flowers as food resources for bees and butterflies. An excellent resource this subject is The Xerces Society for Invertebrate Conservation, a non-profit organization. The Society offers reliable information on all aspects of attracting pollinators.

The Society’s guidelines for California gardeners get to the point:

  • Use local native plants (bees prefer them);
  • Choose several colors of flowers (blue, purple, violet, shite and yellow are good; pink and red not so much);
  • Plant flowers in clumps (a four-foot wide clump of one flower is much better than a scattering of the same number of plants);
  • Include flowers of different shapes (bees come in different sizes and different preferences);
  • Have a diversity of species flowering all season (both the bees and you will appreciate having flowers for most of the year).

Another helpful resource is The Melissa Garden: A Honeybee Sanctuary, which is located in Sonoma County. The owners offer an extensive list of plants that attract bees, and offer tours and classes in beekeeping, attracting pollinators, and related topics. “Melissa” is from the Greek word for honeybee.

Visit ongardening.com for links to The Xerces Society, the Melissa Garden and other resources for attracting pollinators to your garden, as well as for information on organic gardening and integrated pest management.

As you add flowering plants to your garden, choose some for the bees and butterflies.


The Xerces Society

Melissa Garden

Attracting Pollinators to Your Garden Using Native Plants

Organic Gardening: There are many books and magazines on this subject. A classic in the field is Maria Rodale’s Organic Gardening: Your Seasonal Companion to Creating a Beautiful and Delicious Organic Garden (Rodale Press, 1998)

Integrated Pest Management The University of California’s Integrated Pest Management program is a valuable resource for California  gardeners. Another useful resource is the U.S. Environmental Protection Agency’s webpage on IPM Principles.



A Seasonal Pest

For the past several days, I have been pulling oxalis seedlings from my garden. There are 800 species of oxalis, some of which are desirable ornamental plants, but the species in my garden is no prize.

The pest in my garden is Oxalis pes-caprae (Bermuda Buttercup or Sour Grass), a South African plant that has naturalized in the Monterey Bay area’s similar climate. The plant has clover-like leaves and a bright yellow flower. It’s not unattractive, but it reproduces rapidly and could take over the entire garden in time.

Leaves, root, bulblets


It reproduces by multiplying its small bulbs, which are around one-quarter inch in diameter. One bulb can produce ten in a single season.

It’s theoretically possible to excavate 100% of the bulbs, but this is time-consuming and unlikely to be successful.

The most effective approach is “old bulb exhaustion,” which involves removing the top growth before it can flower. In this area, flowering occurs in February, with sunnier spots blossoming earlier than shadier spots. The idea is to deprive the old bulb of nutrients that would be provided by the leafy growth above ground, so that the new bulbs will die off.

It is best also to disrupt the new bulbs by cultivation, but this might be difficult if the pest has started close to desirable plants.

In any event, this process requires tilling to remove any new growth that appears in about two weeks. A Dutch hoe, which is good for shallow cultivation, would make short work of the new growth.

Several products are marketed as controls for this pest and other broadleaf plants: Weed-B-Gon Chickweed, Clover & Oxalis Weed Killer, Roundup, Finale, Oxalis X, etc. I do not use synthetic chemicals in my garden, because of concerns that they will harm plants, beneficial insects, microorganisms and perhaps myself and other mammals, in addition to the plants or pests they are intended to control.

There are less toxic concoctions for controlling this plant. For example, one foliar spray recipe calls for two cups of white vinegar, one teaspoon of baking soda, and one teaspoon of liquid detergent. Reportedly, this spray will kill the oxalis plant’s top growth but not the bulbs. It should not be sprayed on desirable plants.

Another control strategy is let chickens snack on this weed. Reportedly, they like it a lot.

The gardener engaged in weed control adventures can find confidence in the knowledge that no plant will survive the persistent removal of its top growth.

Finally, a frustrating encounter with Oxalis pes-caprae should not bias the gardener against less invasive species from the wood sorrel family. One of my favorite nurseries, Annie’s Annuals and Perennials, lists seven Oxalis species as desirable garden plants.

Enjoy your weed-free garden.


More information on this weed from the California Invasive Plant Council.


Farm Policies Affect Everyone

Last week’s 33rd Annual Eco-Farm Conference, primarily an information-feast for organic farmers, included sessions of relevance for home gardeners and others who buy groceries, i.e., everybody.

The conference included eight-to-twelve workshop sessions at a time, so one can’t attend all sessions of interest. I sat in on sessions on public policies relating to farming. These sessions included updates about the federal farm bill and the GM labeling initiative that Californians voted on in November of 2012 (and did not pass).

Every five years, Congress reviews, revises and updates the farm bill, which is the federal government’s primary tool for agricultural and food policy. This omnibus bill addresses a wide range of matters under the purview of the U.S. Department of Agriculture, including for example, food stamps, food safety, direct payments (subsidies) to farmers, crop insurance, and many other programs. The most recent farm bill, called the Food, Conversation and Energy Act of 2008, authorized $288 billion in federal expenditures. By any measure, the farm bill is major legislation.

The farm bill was to be renewed for 2013, but it became caught up in Washington’s current debate over the fiscal cliff. Congress couldn’t completely ignore these important policies, so it approved a nine-month extension.

Congress extended—but did not fund—several relatively small programs that support progressive agriculture: one that defrays some costs for farmers who convert to organic, one that helps communities launch farmer’s markets, one that funds research on organic farming, and one that helps minority farmers. Still, Congress approved $5 billion for farm subsidies, even though the agricultural lobby had agreed to their elimination. Go figure.

The organic farming community hopes for approval of funding for progressive agricultural programs, and even a modest increase of support. Both optimists and pessimists were at the conference.

The GM labeling initiative would have required food producers to label products that contain genetically modified foods. Consumers supported the initiative strongly, but major food producers and agricultural chemical companies spent lavishly in opposition and the initiative failed by small margin. The supporters of GM labeling are already planning another initiative and confident in its eventual success. Many other states are pursuing legislation or initiatives to require GM labeling.

A potential issue in this campaign is the casual use of both “genetic modification” and “genetic engineering” to mean the same. Meanwhile, some commentators insist that GM includes natural and human-controlled hybridization, a constructive practice that has been followed for centuries. Voters respond badly to ambiguity!

The unique Eco-Farm Conference attracts farmers and other advocates of organic farming and gardening from throughout the United States. It provides great distinction for the Monterey Bay area.


Interesting article: The Threats from Genetically Modified Foods

Grocery shopping advice: How to Avoid Genetically Modified Food – Real Food

Lots of information on GMOs and the labeling initiative is on the website of labelgmos.org.

The farm bill is controversial in several respects. Click here for Wikipedia’s relatively neutral article on the farm bill. To follow the debate, read the newspapers!