- Author: Cheryl Carmichael
Serotiny, n, (Botany)
In botany, serotiny means “following” or “later.”
Serotinous leaves follow flowering on plants: ex. redbud trees leaf out after the flowers on the branches fade.
Serontinous flowers follow the growth of leaves forming serotinous fruit (cones) that release their seeds over an extended period of time or only in the face of environmental triggers. In California, South Africa, and Australia, plants with serotinous fruit include many species of pines, all cypress and sequoia, some spruce, and eucalyptus.
In California, serotinous fruit is an ecological adaptation to regular wildfires. The “fruit” are the cones held high in the canopies of needled trees that can exist for years as sealed containers until bursting open and dispersing seed. These seeds are held in cones by a resin that coats the outside of the cone and glues the “petals” of the cone together. The heat of fire will melt the resin, unfolding the petals and releasing the tiny seeds. The germination of these seeds following fire replenishes the forest with new plant material. The science of “Fire” as an environmental trigger event is called pyriscence, is used synonymously with serotiny and is the most studied case of trigger events.
Other potential trigger events include death of the parent plant or branch, wetting or too much water, excessive sun exposure, drying atmosphere, and fire followed by very wet conditions.
Plants that have leaves and flowers at the same time and drop seeds at maturity during a
growing season are termed coetaneous.
EXAMPLES: CLOSED and OPEN CONES
Aren't native plants supposed to survive on rainfall? Should I water them during the summer? If so, how much?
The answer depends on which plants are living in a particular site. Is the soil loamy, sandy, or heavy clay? What is the sun exposure? The high and low temperatures? How well-established are the plants?
Observing how native plants grow and thrive in the wild is instructive and can guide best practices for home gardeners to use. Note which plants thrive in sunny locations, or near water, or in rocky outcrops. In this photo, it's easy to tell the north-facing from the south-facing slopes.
Watering:
Because most California soil is dry during the summer, many native plants are well-adapted to those conditions and won't tolerate standing water. This is particularly an issue with clay soils that don't drain well. The excess water can cause roots to rot, or it can cause suffocation as the water prevents oxygen from getting to the roots. Watering an established native—meaning one that is 1-2 years old and has at least doubled in size—even just once a month during the height of summer can be enough to kill it.
This is also because California natives, and many other plants, rely on mycorrhizal fungi that live symbiotically in the roots of the host plant. These amazing fungi provide critical micronutrients and increase the absorptive capabilities of the plant's roots by up to one thousand times in exchange for the carbon provided by the host plant. Mycorrhizae even secrete chemicals that help to suppress weeds! However, the bacterial and fungal pathogens that can kill mycorrhizae thrive in warm, moist conditions, so too much watering in hot weather can be deadly for them.
In nature, plants with deep roots—such as oak trees—pull moisture from the water table and share it with other nearby plants. Roots will grow in the direction of a water source, and it is surprising how wide mature root systems are. Many have a root system three times the width of the crown. This illustration shows how the process works.
Knowing this, home gardeners can mimic nature by creating a bioswale, trough, or catch basin that collects water and allows it to be transferred to nearby plants. A garden designed with riparian plants inside a naturally moist or well-watered area with drought tolerant plants nearby takes advantage of this. Local riparian plants include trees such as Acer negundo (box elder), Cornus sericia (creek dogwood), Fraxinus latifolia (Oregon ash), and Salix gooddingii (San Joaquin willow). Riparian perennials and shrubs include Rosa californica (California wildrose), Vitis californica (California grape), and Erythranthe guttata (seep monkey flower). Calscape provides more examples and gives the general water requirements for California natives. WUCOLS IV (Water Use Classification of Landscape Species) is another very useful website for determining the specific water needs of thousands of plants.
Although they may go through a period of dormancy and survive without summer water, most native plants look better with judicious supplemental water. Another consideration is that extremely dry plants pose a fire danger. Some gardeners aim to shorten the period of summer dormancy by extending the watering period in the spring and fall. But it is important not to waste water by overwatering plants, particularly during drought conditions.
This may translate to watering young plants every week or two and established plants once a month. In general, established native plants should be watered deeply but infrequently enough to allow the soil to dry out in between watering. The top few inches should remain dry around small plants, deeper with mature plants. To water deeply, it is necessary to water slowly, allowing the water to soak in. If a heat wave is predicted, water before—rather than during—the worst of the heat. Watering early in the morning on a relatively cool day is best. Rinsing the dust off the leaves occasionally also helps plants look their best.
If drip irrigation is used, move the water source farther from the center of the plant as it grows. It is best to have several emitters per plant, placed at the plant's drip line. A single drip emitter near the crown encourages a small root ball and makes the plant more susceptible to rot and diseases.
Overhead sprinklers do not work well with most non-riparian native plants. A light watering that simulates a summer storm early in the morning will probably not harm the plants, but anything placed close to a sprinkler head will probably get too much water. Light hose watering is a preferable way to water, but not directly on the crown of the plant. It's better to spray the water around the drip line, a few feet away from the root ball.
Whatever method is used, it is important to check the soil before watering rather than to keep to a schedule. If the soil is moist at the root level—checked with a moisture meter or simply by poking a finger into the soil—it is not time to water, even if the surface appears dry. When in doubt, do not water! But continue to monitor the plant, especially if newly planted. Wilting leaves are not necessarily a sign that water is needed; confusingly, they can also indicate root rot caused by too much water.
Mulching:
Gardeners can take a cue from nature again regarding mulch. Many native plants create their own mulch with leaf litter. This type of mulch tends to be light and airy, allowing for good airflow. It doesn't wick moisture up from the soil, but still shades the roots, suppresses weeds, and helps maintain soil moisture and temperature. It also improves soil as it decomposes. So leaving leaves in place is a good practice, whenever possible.
Some natives, particularly desert and prairie plants, do well with gravel or rocks as mulch. Wood chips or bark work well with most other others, and shredded redwood bark is best for coastal and Sierra natives. Many do well with a large rock placed nearby.
Mulch should be 2-3” thick and kept away from the trunks or stems of plants. Ideally it is applied in the spring or fall, but more can be added in the summer if it is too thin, for all the benefits mentioned above.
Deadheading and Pruning:
Many native plants—including Monardella villosa (coyote mint), Verbena lilacina (lilac verbena), Mimulus spp. (monkeyflowers), Penstemon spp. (penstemon), Eschscholzia californica (poppies), and Salvia spp. (sages)—respond well to deadheading with new blooms, though some gardeners choose to leave the seeds for reseeding or for their value to wildlife.
Summer is a good time to tip pinch shrubs if you want to encourage denser growth. It is also a good time to thin or prune shrubs and trees, if necessary. Native evergreen trees are susceptible to disease if they are pruned in wet weather, so summer is a better time to prune them. Because requirements vary with different plants, it is best to check for reliable information on specific plants before pruning them and to use the services of a qualified arborist for pruning large trees.
Takeaways:
- Mimicking nature as much as possible with plant placement, watering, and mulching is a good way to be successful with California native plants.
- Checking the moisture level at the root ball is important. Allow the top few inches of soil to dry out between waterings.
- Watering deeply and infrequently is recommended for most non-riparian natives, but watering needs vary with environmental conditions and the age of the plant.
- Take advantage of resources such as Calscape and WUCOLS IV for detailed information on thousands of plants.
- Many native plants respond well to deadheading, tip pinching, and pruning during the summer; look at the requirements for specific plants.
For more information:
Bornstein, C., Fross, D., and O'Brien, B. (2005). California Native plants for the garden. Cachuma Press.
California Native Plant Society: Mulching basics. https://www.cnps.org/gardening/prepping-and-planting/mulching-basics
California Native Plant Society: Watering California native plants https://www.cnps.org/gardening/prepping-and-planting/watering
Calscape California Native Plant Gardening Guide. https://calscape.org/planting-guide.php
Las Pilitas Nursery: How to plant California native and other drought tolerant plants. https://www.laspilitas.com/planting.htm
Popper, H. (2012). California native gardening: a month-by-month guide. University of California Press.
- Author: Flo Pucci Master Gardener
The promise of warmer temps is a welcome reprieve from bulky clothing and enclosed environments after a cold, foggy, and windy winter. Indeed, warmer temperatures provide the perfect envelope for outdoor activities like backyard BBQs, swimming, and gardening. However, not all is fun and bliss during the warmer months; a vital detail that should not be overlooked is the troublesome mosquitoes that can dampen outdoor activities. In many areas of California, public mosquito and vector control agencies aim to keep mosquito numbers down to tolerable levels all or most of the time.
UC Master Gardeners Integrated Pest Management strategies (IPM) offer the following tactics to reduce or eradicate the mosquito population in your community. Keeping fine mesh screen on windows and outdoor in good repair, draining standing water or treating it with a control agent such as Bacillus thuringiensi subspecies israelensis (Bti), incorporating mosquito-eating fish into isolated ponds and neglected swimming pools, and wearing repellent and protective clothing outdoors when mosquitoes are active.
When the mosquito population becomes bothersome, people can protect themselves and others by applying a mosquito repellent. The Center for Disease Control and Prevention (CDC) recommends using products containing active ingredients registered by the U.S. Environmental Agency (EPA) as repellents applied to skin and clothing.
An EPA registration indicates the active ingredients of the repellent have been tested for human safety when used according to the instructions on the label. The CDC currently recommends two types of repellents for skin use: conventional and biopesticide repellent. Conventional repellent includes compounds such as DEET and Picaridin (KBR). Biopesticides repellent are derived from natural materials or synthetic versions of the natural product, such as the synthetic oil of lemon eucalyptus (OLE: use only when formulated as a repellent. The EPA does not currently register the pure form of OLE). DEET is the most effective mosquito repellent if you will be out for long periods where mosquitos are abundant. However, DEET is an irritant to some people, and repellents containing high concentrations of DEET can damage synthetic materials such as clothing or plastics. Special low formulations of oil-based mediums that slowly release the compound and limits the absorption throughout the skin are good for children and adults.
Mosquitoes, like all creatures, are attracted to environments that contain the things they need to live, including certain plants. Mosquitoes do not live on blood alone. Only the female bites and feeds the blood to their eggs. Adult mosquitoes eat the nectar of certain plants, such as Taro, papyrus, water lilies, and water hyacinths. Therefore, removing these plants help reduce the mosquito population in your community.
Here are a few plants worth having in the garden that are not only pretty but can help in the constant war against bugs and will help make outdoor activities fun and blissful for everyone. Peppermint, Lemon Balm, Lavender, Catmint, Basil, Mint, Sage, Rosemary, Marigold, Geranium, Mum, Thyme, Eucalyptus,
Hummingbird Mint, Lemongrass, Society Garlic, and Lemon Verbena are all beautiful additions to a garden.
In short, in addition to growing the plants listed above, homeowners should practice the control practices approved and recommended by the Mosquito Vector Control District as well as UC Master Gardeners Integrated Pest Management strategies in their homes and community so that mosquitoes do not get out of hand.
Please follow the links below for more in-depth information about mosquito control in your area.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7451.html
http://sjmosquito.org/Mosquitoes-Ticks/Mosquito-Prevention-Tips
- Author: Regina Brennan, Master Gardener
I was recently reminiscing with one of my grandsons about the fun times we had when he was little, and we played in my garden together. In all honesty, grandma had different warm memories than that little guy, who is now in his second year of college. I, of course, was hoping for affirmation of the strongly held belief that involving children at an early age in age-appropriate gardening activities will ensure a lifetime of love of gardening.
As with any learning, repetition is important for the strengthening of retention. For parents, involving children in the cycle of growth and seasons has a better chance of retention than a “one and done.”
For myself, as a child, I learned to love sitting in the garden quietly observing the sights and smells of a wide variety of flowers and shrubs. I was four years old, and the garden belonged to our landlord, and my parents rented an apartment from them. It was a magical time for me, as there were no playmates my age. I was allowed to sit in my little rocker chair by myself because I didn't get into “mischief.” I look to that time as the beginning of my love of the outdoors, especially the peace and joy of being alone with nature.
Fast forward to present day, and I still find myself going out to my garden when I am feeling stressed, overwhelmed, or just plain cranky. I suspect every parent and grandparent wants to pass along the love of the outdoors, and particularly the love of gardening, to their children and grandchildren. In today's stressful and often toxic environment, being able to retreat for a short time to reclaim a sense of stability and calm is something we can achieve without waiting for the weekend and a long drive to find a reprieve from built up stress.
Children mimic the actions and attitudes of the significant adults in their lives. Involving them in the planting and general
Gardeners are made, not born, is a fairly common expression that illustrates the importance of involving children at all ages in the growing of a garden. Small children love to help in just about every gardening activity, and extra patience needs to be shown to not discourage their joy and wanting to help. The other half of this reality is when the children are finally old enough to really be of help, they lose interest and want to be out playing with friends. Parents are competing now with electronic devices for the attention of their children. It is increasingly difficult for parents to make the time to work with their children to instill in them the value of real life experiences. Not all is lost, however. Google can be used by school age children as a resource and teaching tool for plant identification and care!
Back to childhood memories of outdoor spaces and the sights and smells of lovely gardens. As parents and grandparents, we hold on to the belief that our efforts to raise our children will eventually bear the best kind of fruit: love of nature, and gardening in particular. Even if the younger ones lose these precious memories with time, we can still hang on to our own, and enjoy the warm feeling of accomplishment of having planted the seed in our next generation of gardeners.
- Author: Sue Davis, Master Gardener
As the summer swelters on, we can all be thankful that there are only four big things to think about each month. Be smart about sun exposure and work in the early mornings or spread the chores across several days if needed.
July Ideas
ONE –WATER – We are officially facing another drought year, so conservation of as much water as possible in the landscape is an imperative. Do not water mature, native California oaks. To save mature, drought tolerant trees, deep water only once per month. Mature fruiting and most ornamental trees growing in our clay-loam soil will need a deep irrigation every 14 days. Mature citrus trees can go about 10 days between deep irritations. Potted trees are not good conservers of water. They need to be checked, and in some cases, watered daily.
THREE – It's hot outside, but the need to garden continues. Try making an open terrarium filled with succulents. Place a layer of stones plus some horticultural charcoal at the bottom of a glass container. Top the stones and charcoal with a thin layer of moss and some soil. Add succulents, a decorative item or two, and water gently. Let the soil dry out completely between watering.
FOUR – Avoid harboring pests that will affect next year's production by cleaning up mummies and old fruit and nuts in and under trees.
In August
ONE – Take some time during these dog days of summer to enjoy the landscape and garden while planning a winter garden and deciding on landscape additions. Select seed, gather whatever soil amendments, tools, and irrigation supplies are needed, and find where that perfect plant, shrub, or tree can be purchased. Visits to nurseries are a great way to beat the heat.
TWO – It is time to think of a cool season vegetable garden. Just saying those words, like a mantra, may bring some
THREE – Apricots and cherries should have their final pruning this month. Pruning during the wet, winter season could lead to detrimental canker infections in the trees. The pathogens for these diseases are spread by rain or tree wounds (like pruning cuts) during wet weather and continue to spread through the wood of the tree for several years.
FOUR –Note Lee Miller's Help Desk article in this Blog and plant a bed of strawberries this month for an abundant crop next year. Since plants only produce well for about three years, try only planting a third of the patch this year, adding a third next year and a third the following year. Planting on a rotation like that will result in a consistent yield and not be such a daunting task in the heat of summer.
September Notes
ONE – While people might like the coming of cooler weather that September signals, so do fleas! Be sure to groom and monitor pets during the cooler months of autumn to detect the beginning of any infestation. In California, Cat fleas, Ctenocephalides felis, are most common on domestic cats and dogs. Although dog fleas look like cat fleas, they are rare in our state. Adult fleas are no larger than 1/8 inch long, so it is difficult to see a number of the characteristics used to describe them. These reddish-brown, wingless insects are laterally compressed, so they look as if they are walking on edge. Cat fleas have both pronotal and genal combs. For more information on these unwanted insects which can also infest a home if left unchecked, see the UC IPM pest notes on fleas.
TWO – Landscapes can be brightened by setting out transplants of a variety of flowers found in local nurseries. Favorites include pansies, verbena, dianthus, and mums. If there is room, plant a tree on the southwest side of a dwelling to provide shade in the coming years. Be sure to check the mature size (both width and height) of the tree to know if there will be ample room once it reaches maturity. Shrubs and groundcover that are beginning to look a little bedraggled should be replaced as the weeks begin to cool. If this is a more bountiful year for water, nature should do most of the fall and winter watering to develop a strong root structure and beautiful new growth starting next spring. If we are facing another dry winter, remember that even “low water” and “drought resistant” plants need consistent watering until they are established.
FOUR – In case rain is sparse again this year, organic mulch applied several inches thick around plants will help keep roots moist. Keep the mulch 3-5 inches from the trunks of plants to avoid problems with rot. This is basically just good practice in the landscape whether or not there is ample winter rain.
Information for this article has been gathered from: