Ann Wright: Spring garden surprises |

Ann Wright: Spring garden surprises

Part of the fun with gardening are the surprises that may arrive at any given time, such as a volunteer flower or vegetable, a mysterious series of holes in the ground, or perhaps some lacey patterns carved out of leaves of sunflowers. Figuring out why the surprises are gracing your garden is part of the “good news, bad news” scenario that presents itself. The good news may be that the volunteer is from a flower that you love that has re-seeded, the bad news – you don’t want it where it grows. With the holes in the ground – this may be just bad news – as in rodents. If you watch your sunflowers later in the summer, you may notice little birds, like finches pecking at the leaves -surprise! Good news – birds are happy, bad news – skeletons for leaves.

Integrated Pest Management (IPM) is a strategy to help manage garden surprises. The process of IPM involves identification of the “surprise” in the garden, determining how much it interferes with your garden plan or tolerance, and then how to manage it. Once the pest or disease is identified, ongoing assessment and prevention of future surprise invasions follow.

To better help identify pests, observe what is happening with the plants in a given area. Are there visible insects chewing on leaves, or is there goo arising out of the bark of a tree? Observations will help target research as to what the pest is. Night-time visits to the garden with a flashlight may reveal way too many bug parties.

Once the pest has been identified, assess the amount of damage – is an army of caterpillars camping out on your favorite plum tree, or just one or two that can be easily picked off and removed? Get out in the garden often just to observe and see how things are growing. If the army of caterpillars is beyond what can be tolerated, a management strategy can then be planned.

Integrated Pest Management offers several tools in the armory – some a bit more involved than others, but all within what home gardeners can do. Biological control is observed as the pest’s natural enemies help control the population of the pest. For example, an abundant aphid population may be kept at bay with lady beetles (also known as lady bugs) lace-wings or other beneficial insects.

Cultural controls are achieved by modifying normal plant care activities to reduce or avoid pest problems. Examples are changing irrigation practices to only water the plant – not the weeds, or planting disease resistant species of plants. Mechanical control utilizes materials or physical means to kill or block out pests. Examples are gopher traps, mulch to suppress weeds, trimming infested branches from a tree, etc.

Chemical control includes the use of pesticides or other chemicals to control a particular pest. Integrated Pest Management recommends that chemical control be used in combination with other approaches and only when necessary, for more effective long-term control. Selection of a pesticide is recommended only in ways that are the least toxic to people, non-target organisms such as bees and other beneficial insects, and the environment. Careful consideration of chemical pesticides requires close observation of what is going on in the garden – perhaps other components of IPM would be effective enough to decrease the pests to a tolerable level. It is essential that any use of chemical means to control pests be done carefully, incorporating other IPM strategies in combination with chemicals. Read all instructions and ensure the chemical is the most effective for the pest in your garden. Observe all safety practices and use only the recommended amount to control undesirable pests.

An example of a surprise this spring in my garden was the invasion of something attacking the Mariposa plum tree. The tree bloomed beautifully this spring; leaf shoots came out but has it has not set any fruit. Now, the leaves are curled, mangled and quite distorted. This tree had the same issue last spring, but it was not treated during the dormant season, and the pests are back. So, to the IPM resources we go.

After looking closely at the leaves – particularly the underside of the curled mess, it appears that aphids are the likely culprits. In looking closer, it seems that the leaf curl plum aphid (brachycaudus helichrysi) has been thriving on the tree – perhaps since last year. So, with the help of the UC Davis IPM website ( the tree will be treated with a sharp spray of water mixed with horticultural and neem oil. Assessment will continue and treatment will be done again in the fall after leaf drop. (Leaves or cuttings from the infested tree should not be composted. Rake and dispose of leaves carefully away from other plants.) Additionally, next spring the tree will be inspected and treated carefully. A sticky barrier will be placed around the trunk of the tree to help prevent ants from getting into the tree – ants carry aphids into the new growth of the tree and they help protect aphids from predatory insects.

To learn more about IPM and how to use these strategies in your gardens, join the Master Gardeners of Nevada County for a live Zoom workshop, “Integrated Pest Management for the Modern Gardener” to be offered in two parts – the first, today at 9 a.m. Part 2 will take place at 9 a.m. on June 5. To access the Zoom workshops, go to the website at and click on the link to the Zoom session. Other workshops are also listed on the website as are the recordings of past workshops.

Ann Wright is a Nevada County Master Gardener.

Damage to plum tree likely from aphids.
Photo by Ann Wright
Distorted leaves on a plum tree. To learn more about IPM and how to use these strategies in your gardens, join the Master Gardeners of Nevada County for a live Zoom workshop, “Integrated Pest Management for the Modern Gardener” to be offered in two parts.
Photo courtesy UCANR

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