- Author: Denise Godbout-Avant
As the long, hot days of summer slide into cooler, shorter days of autumn, seasonal changes are occurring in my garden. Not as many plants are blooming, the leaves on deciduous trees and plants are becoming drier and starting to change color. Some plants are producing autumn berries that will sustain many birds as insects, another source of food, begin to disappear.
Quite a few butterflies have been showing up in my garden to take advantage of flowers that are still blooming. Butterflies I have been seeing include painted ladies (Vanessa cardui), common buckeyes (Junonia coenia), fiery skippers (Hylephila phyleus)and cabbage whites (Pieris rapae).
With the advent of winter, butterflies disappear since they cannot tolerate temperatures below 55°F or rainy weather. So, what happens to butterflies in the winter???
Some Butterflies Migrate
Some butterfly adults migrate south, overwintering in warmer climates.
Monarch butterflies are known for their astonishingly long spring and fall migrations. Both the eastern monarchs and western monarchs began their southern migrations in late August or early September from southern Canada/northern USA to their overwintering sites. The eastern variety generally heads to the oyamel fir forests in the mountains of central Mexico, whereas the western Pacific species have a shorter journey to California's coastline. You may see some western monarchs this fall resting or feeding on flowers in your garden as they fly through the Central Valley on their way their overwintering sites in coastal areas such as Santa Cruz, Pacific Grove, Pismo Beach, and San Diego.
Other Winter Strategies
Most butterflies spend winter in the same area they spent summer.
Some lay their eggs in autumn on, or close to, their specific host plants with the eggs hatching the following spring. The common hairstreak (Satyrium californica) eggs are laid attached to twigs of oaks with the caterpillars feeding on newly emerged spring leaves.
Some butterflies weather the cold as pupa within a chrysalis in a sheltered spot. During this time, the pupa will enter diapause (where development stops). An antifreeze chemical in their blood allows them to survive cold temperatures. Once the days lengthen, it will resume its transformation, emerging as an adult just as in time for blooming flowers that provide nectar. The tiger swallowtail's chrysalis (Papilio rutulus) will take refuge in deep shrubbery. The anise swallowtails (Papilio zelicaon) and cabbage whites also generally overwinter as a pupa in their chrysalis. Fiery skippers usually overwinter as pupae buried in leaves, but some adults will migrate to southern California.
Mourning cloaks (Nymphalis antiopa)go into dormancy as an adult. Their blood also contains an anti-freeze. They tuck themselves into cracks and crevices of rocks and trees.
Leaving the Leaves
- Learn which butterflies live in your area and grow native plants for those specific species.
- Offer nectar plants in the fall and spring months for butterflies that are migrating, emerging from overwintering, or getting ready to go into winter dormancy/hibernation.
- Skip raking the leaves in your garden in autumn and leave standing plants alone until midspring, so overwintering butterfly larvae, pupae and adults have a place to hide. If leaving the leaves on your lawn is too messy for you, consider not disturbing the leaves in your planters.
- If you find what looks like a dead chrysalis (many resemble dead leaves) in your yard, garage, shed, do not disturb it. A butterfly may well emerge in the spring.
- Avoid using pesticides as much as possible.
Resources
- Art Shapiro's Butterfly Site: https://butterfly.ucdavis.edu/butterflies
- Butterflies in Your Garden, Publication from UCCE Stanislaus County :https://ucanr.edu/sites/CEStanislausCo/files/345791.pdf
- Xerces Society - Pollinator Plants: Central Valley of California: https://xerces.org/publications/plant-lists/ppbi-california-central-valley
- California Native Plant Society: https://www.cnps.org/
- UC Davis Arboretum – Larval Hosts for Butterflies: https://arboretum.ucdavis.edu/blog/larval-host-plants-butterflies
Denise Godbout-Avant has been a UC Cooperative Extension Master Gardener in Stanislaus County since 2020.
/h3>/h3>/h3>/h3>Learn about planting leafy vegetables like lettuce and spinach, and root vegetables like carrots, beets and radishes. Not to mention broccoli and cauliflower. All of these vegetable plants can be grown in the ground or in containers. Great class for beginning gardeners.
We are excited to say that our classes are at nine Stanislaus County Library Branches! We hope to see you there.
August 2023 Library Branch Schedule
- Tuesday, 8/1 at 6:00 p.m. - Salida
- Saturday, 8/5 at 2:00 p.m. - Empire
- Tuesday, 8/8 at 6:00 p.m. - Oakdale
- Thursday, 8/10 at 1:00 p.m. - Patterson
- Saturday, 8/12 at 2:00 p.m. – Riverbank
- Monday, 8/14 at 6:00 p.m. – Ceres
- Tuesday, 8/22 at 2:00 p.m. - Waterford
- Wednesday, 8/23 at 6:00 p.m. - Turlock
- Monday, 8/28 at 5:30 p.m. - Modesto
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Citrus trees need care throughout the year, including cultural practices to keep trees healthy and pest management. During the fall season, several pests can attack citrus trees in many California regions.
Brown Rot
Monitor for this disease by checking for damaged fruit on your tree, as well as fruit in storage. Sometimes affected fruit develops a pungent odor and can ruin fruit held in storage. See the UC IPM web page on Brown Rot to learn more.
If you see what look like small “tunnels” on your citrus tree leaves, your tree might have citrus leafminer. The adult stage of this pest is a small, light colored moth; the larval stage feeds and develops inside the leaves of young citrus and other closely related plants.
Citrus leafminer rarely causes problems for mature trees, however, it can seriously damage very young trees. Read the UC IPM Pest Notes: Citrus Leafminer for recommendations for prevention or management.
Snails and Slugs
Asian Citrus Psyllid and Huanglongbing
You may have heard of the Asian citrus psyllid (ACP) and the deadly disease huanglongbing (also called citrus greening) that has been featured in the news. This disease doesn't pose a threat to humans or animals, but is deadly to citrus trees. Once a tree develops huanglongbing, there is no cure, so for this disease prevention is key.
UC IPM Web Site
For information on managing other citrus pests in the garden, see the UC IPM webpage on Pests in Gardens and Landscapes: Citrus.
- Author: Denise Godbout-Avant
People often rake their leaves and put them out to be picked up as trash. I have always preferred to leave the leaves for my garden.
If you take a walk in a forest, you'll see leaf layers several inches deep around trees and bushes. Fallen leaves have a complex relationship with trees and nature, providing many benefits which can be reproduced to some extent in our gardens.
Natural Mulch
Fallen leaves have the same weed suppression and moisture retention properties of shredded wood mulch—and they're free! Where mulch is desired as a decorative element, what could be more seasonally appropriate than a pile of brightly colored fall leaves? This natural mulch also provides insulating winter cover from cold temperatures for roots, seeds, and bulbs.
A Web of Life in Leaf Litter
Leaf litter isn't just free fertilizer and mulch. It provides food and shelter for a wide variety of living things including spiders, snails, worms, beetles, millipedes, mites, toads, frogs and more—these in turn support mammals, birds, reptiles, and amphibians that rely on these creatures for food.
Detritivores (organisms that eat dead or decaying plants or animals) break up and excrete leaf litter. Fungi and bacteria then take over and complete the recycling process converting these smaller pieces into nutrients which then sustain neighboring plants. They in turn help support biodiversity by becoming food themselves.
Numerous bird species such as robins and towhees forage in the leaf layer searching for insects and other invertebrates to eat.
Raking up leaves and putting them in the trash could have the unintended consequence of removing some of next year's garden butterflies and moths, many of which are pollinators. Most butterflies and moths overwinter in the landscape as an egg, caterpillar, chrysalis, or adult. In all but the warmest climates, they often use leaf litter for winter cover. Fritillaries and wooly bear caterpillars will tuck themselves into a pile of leaves for protection from cold weather and predators. Some Hairstreaks lay their eggs on fallen oak leaves, which become the first food of the caterpillars when they emerge. Swallowtail butterflies disguise their cocoons and chrysalises as dried leaves, blending in with the “real” leaves.
Bumble bees also rely on leaf litter for protection. At the end of summer, mated queen bumble bees burrow an inch or two into the earth to hibernate for winter. An extra thick layer of leaves is welcome protection from the elements.
All of which makes leaf litter an integral part of a complex web of life.
What You Can Do
Composting leaves is a terrific way to recycle and create a nutrient-rich garden soil amendment at the same time. Some gardeners opt for shredding their fall leaves for use in compost piles. Like people who mulch their lawn leaves with a mower, consider leaving some leaves undisturbed in garden beds and lawn edges. If space allows, you could create a leaf pile, allowing it to break down naturally, or add the leaves gradually to your compost pile over time. Such efforts will keep leaf litter critters safe and allow you to benefit from the rich garden gift that falls from the trees above.
While it is ideal to “leave the leaves” permanently—for the benefits mentioned above—if you do decide you need to clean your garden and remove the leaves in spring, try to wait until later in the season, so as to give the critters that have been protected by fallen leaves over the winter time to emerge and depart.
Some gardeners may be concerned that autumn leaves, matted down by rain or snow, could have a negative impact on their perennials. However, a thick layer of leaves provides additional insulation against chilly weather and protects newly planted perennials from frost which could damage tender roots and shoots. Anyone who has spotted fragile spring seedlings popping up in the woods knows that all but the most fragile of plants will erupt through the leaf litter in spring without trouble.
So, leave the leaves. While you can't perfectly emulate a forest, your garden will be healthier and more diversified, you'll help support a vast array of wildlife, and you'll reduce the strain on landfills.
Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020.
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