Plan your pest control tasks with IPM Seasonal Landscape Guide
Removing leaves and fruit from underneath trees reduces pathogen growth and rodent infestations. (Jodi Bay)
UC site maps out a month-by-month checklist on preventative measures and management techniques
By Jodi Bay
(This article originally appeared in the January 11, 2025 edition of the San Diego Union-Tribune)
It’s the beginning of 2025 and the cusp of another year of gardening. Gardening has seasons where plants grow best, flowers bloom, vegetables provide their fruit, and pests invade your garden. Many of the pests and pathogens that stalk your garden are seasonal, i.e. appear only at certain times of the year.
To help you plan for and prevent this upcoming nuisance, the University of California has created a monthly calendar of gardening tasks and potential pest problems, by region, for the home gardener.
The website with the UC IPM Seasonal Landscape Guide shares research-based, scientific information on monthly gardening tasks. You’ll learn how to keep your garden healthy, which pests are active during the month, and the best remediation for effective control using the least toxic methods first. This process is called Integrated Pest Management (IPM).
Go to bit.ly/IPMSeasonalChecklist and select the region in which you are located. This will take you to a month-by-month description of gardening tasks and preventative measures for the garden. In addition, you can sign up for a free monthly email newsletter.
Some garden tasks are most impactful if done monthly. From the UC website, here are some basic steps to help keep your garden healthy:
• Remove detritus: Clean up mummies and old fruit and nuts in and under trees to avoid harboring pests. Remove fallen leaves from beneath deciduous fruit trees and roses.
Mulch, such as wood chips, helps to reduce weeds and conserve water. (Jodi Bay)
Some garden tasks are most impactful if done monthly. From the UC website, here are some basic steps to help keep your garden healthy:
• Remove detritus: Clean up mummies and old fruit and nuts in and under trees to avoid harboring pests. Remove fallen leaves from beneath deciduous fruit trees and roses.
• Manage irrigation: Adjust watering schedules according to the weather and plants’ changing need for water. Reduce irrigation frequency or turn off systems if rainfall is adequate. Irrigate deeply but infrequently if the winter is dry.
• Mulch: Apply organic mulch where thin or soil is bare beneath trees and shrubs.
• Remove weeds: Manage weeds using nonchemical methods such as cultivation, hand weeding or mowing.
• Fertilize: Feed caneberries, citrus, deciduous fruit trees, palms, and heavily flowering shrubs with slow-release product.
• Compost: Turn and keep moist. Cover if raining.
Also from the UC website are some (but not all) monthly gardening tasks such as:
January
• Prepare for rainfall. Prevent water from ponding around trunks and foundations. Improve drainage. Install downspout diverters to direct runoff into landscape soils, but avoid water-logging of soil.
• Plant bare root deciduous trees, shrubs, and vines, such as caneberries, fruit and nuts, grapes and roses.
February
• Implement disease and insect control for apple, pear, stone fruits, nut trees, and deciduous landscape trees and shrubs such as roses.
• Prune deciduous trees and shrubs that need pruning, such as apple, crape myrtle, pear, rose, spirea and stone fruits.
• Yellowjackets: Place out and maintain lure traps or water traps. Trapping is most effective during late winter to early spring.
Ants and aphids work together. The aphids produce a honeydew that feeds the ants. In return, the ants protect the aphids from predatory insects. (Unsplash)
March
• Ants: Manage around landscape and building foundations, such as using insecticide baits and trunk barriers.
• Aphids: On small plants, spray a strong stream of water or apply insecticidal oils and soaps. Look for and conserve natural enemies such as predaceous bugs, lacewings, lady beetles, and syrphids.
Oxalis is a common weed in California that frequently appears in lawns, flower beds, gardens, nurseries, and greenhouses. (Jodi Bay)
April
• Fire blight: Look for oozing and dead limbs on pome plants such as apple, crabapple, pear, and pyracantha. If a problem in the past, apply blossom sprays to prevent new infections.
• Grape diseases: Monitor for powdery mildew, Eutypa dieback, Phomopsis cane and leaf spot, and others. Prune, remove, or treat as appropriate.
May
• Citrus: Monitor for damage and pests such as caterpillars and scales.
• Cover fruit trees and grapes with netting to exclude birds and other vertebrate pests.
Pruning roses helps to keep the plant healthy and encourages flowering growth. (Jodi Bay)
June
• For camellia, citrus, gardenia, grape and other plants adapted to acidic soil: If leaves are yellowing (chlorotic) between green veins, plants may benefit from foliar or soil application of iron and zinc chelate and mulching.
• Lightly prune roses to promote fall flowering.
July
• Mosquitoes: Eliminate standing water e.g., in gutters, drain pipes, and flowerpots. Place Bacillus thuringiensis subspecies israelensis in birdbaths and ponds to selectively kill mosquito larvae.
• Plant frost-tender species, e.g., avocado, bougainvillea, citrus and hibiscus. Water regularly to keep root zone moist, but not soggy.
Common dandelion is a perennial broadleaf weed that grows in a variety of environments throughout California. (Jodi Bay)
August / September
• Eutypa dieback: Prune apricot and cherry to address this disease.
• Spider mites: Irrigate adequately, mist leaf undersides daily, reduce dustiness, spray horticultural oil.
October
• Continue rainy-season prevention of diseases, earwigs, snails and slugs and weeds.
• For pine bark beetles, pitch moths, western gall rust, and wood borers: If pines need branch removal, prune during October through January.
November
• Frost: Protect sensitive plants from cold injury when freezing or frost are predicted.
• Petal blight of azalea, rhododendron and camellia: Remove and discard old flowers. Apply fresh organic mulch beneath plants.
December
• Peach leaf curl: Apply preventive spray once or more during late fall through bud break if leaf curl has been a problem on nectarine or peach.
The UC also provides “Pest Notes” with details on how best to identify and manage garden pests: Visit ipm.ucanr.edu/PMG/PESTNOTES/.
By following these garden maintenance steps and implementing IPM, your garden will be healthy with lower long-term maintenance, and will reward you with beauty and abundance.
Bay has been a Master Gardener since 2012. She is past chair of the Tool Care Committee, and an instructor in the Beginning Vegetable Gardening workshops which teaches new gardeners how to grow healthy and bountiful vegetables.