Leaf Litter Is Perfectly Natural

Mulch merely substitutes for leaf litter.

Forests lack gardeners. In the wild, there is no one to rake fallen leaves or blow them away. Foliage falls from trees and onto the ground, where it stays as it decomposes. It is the natural process. Raking and blowing leaf litter away is unnatural. It deprives the soil and organisms that inhabit it of significant organic matter that they crave. It also interferes with insulation and moisture retention.

Of course, there are some natural processes that are not so desirable in home gardens. After all, that is why raking and blowing is standard procedure. It is not practical to leave leaf litter on lawn, ground cover, pavement or roofs. Raking and blowing removes leaf litter from where it is unwanted, or at least moves it to where it is less visible. Leaf litter seems to be so useless and unwanted.

However, other procedures are necessary to compensate for the lack of leaf litter. Mulching insulates soil, retains soil moisture, and inhibits weed growth. Watering adjusts to deficient moisture in exposed soil. Weeding eliminates weeds that germinate and grow where there is nothing to inhibit them from doing so. Herbicide may be more practical. It is all so contrary to natural processes.

It is somewhat obvious why deciduous plants defoliate through autumn and winter. They do not need their foliage as much while days are shorter and sunlight is less intense. Also, they do not want to be battered by winter wind, or collect heavy snow. Yet, their desire to mulch their own soil is not so obvious. Evergreen plants do it also. They just do it slower, and generally throughout the year.

In fact, many evergreen plants are more efficient with their mulch than most deciduous plants are. Leaf litter of eucalypti, camphor, bay and nearly all conifers actually has a preemergent herbicidal effect. It inhibits germination of seed that can reach the soil. It can be a disadvantage for wildflowers, or an advantage for weed control. Incidentally, coniferous leaf litter is likely to be combustible.

Leaf litter, composted or left to its natural processes, is natural.

Collect Fallen Leaves Before Winter

Falling leaves will soon be accumulating in gutters.

The problem with all the colorful foliage that adorns so many of the deciduous trees in autumn is that it does not stay in the trees too long. Combined with all the other less colorful deciduous foliage, as well as whatever evergreen foliage happens to fall this time of year, it will become quite a mess by winter. Rainy and windy winter weather will only make it messier by bringing down even more foliage!

Contrary to popular belief, many evergreen trees are just as messy as deciduous trees are. Instead of dropping all their foliage in autumn or winter, most evergreens drop smaller volumes of foliage throughout the year. The mess is less obvious since it sneaks up slowly, but can accumulate over a few months. Only a few evergreen trees drop much of their foliage in more obvious seasonal phases.

Debris from evergreen trees is actually more likely to be a problem for plants below. Pines, cypresses, firs, spruces, cedars, eucalypti and many other evergreen trees produce natural herbicides that inhibit the emergence of seedlings of plants that would compete with them in the wild. In landscape situations, this unfortunately interferes with lawns, ground covers and annuals. Besides walnuts and deciduous oaks, not many deciduous trees use this tactic.

Regardless, any foliar debris can be a problem if allowed to accumulate too long. Large leaves, like those of sycamore, can accumulate and shade lawn, ground cover and some dense shrubbery, and can eventually cause mildew and rot. Finely textured foliage, like that of jacaranda or silk tree, can sift through most ground covers to the soil below, but can still make a mess on lawn.

Before rainy weather, debris should be cleaned from gutters and downspouts. Because some foliage continues to fall through winter, gutters will likely need to be cleaned again later. Flat roofs and awkward spots that collect debris, such as behind chimneys, should also be cleaned.

Gutters at the street are more visible and accessible, so do not often accumulate enough debris to be a problem, but may need to be cleaned if they become clogged with debris washed in by the earliest rains. Fallen leaves should be raked from pavement so that it does not get dangerously slippery, or stain concrete too much.

Color Is Not Black And White

Annuls must change with the seasons.

Several months ago, warm season vegetable plants replaced cool season vegetable plants. More recently, new cool season vegetable plants began to grow from seed, to replace warm season vegetable plants. Annual vegetables grow only within specific seasons. As they finish, they relinquish their space to those that grow in the next season. Annual color operates in the same manner.

‘Color’ is another word for ‘annuals’ or bedding plants that provide colorful bloom. Those that grew earlier were warm season annuals or summer annuals. Those that replace them through autumn are cool season annuals or winter annuals. Of course, there is nothing black and white about color. Some color from last summer can linger late. Some for next winter prefers an early or late start.

Furthermore, much of the color that cycles through gardens as annuals actually has potential to perform as perennials. If cut back and obscured by more seasonable color through their dormancy, some types can regenerate when it is again their season to perform. For example, cut back busy Lizzie that bloomed last summer can overwinter underneath primrose, and start over next spring.

Marigold and chrysanthemum can start bloom early, before summer ends, but may not perform for long. Some chrysanthemum bloom only once, before vacating their space for other cool season color that does not mind starting later. Cyclamen and ornamental cabbage happen to prefer late planting, to avoid Indian summer. Warmth causes cabbage to bolt, and promotes rot of cyclamen.

Pansy, viola and various primrose have always been popular. Sweet William, Iceland poppy and stock are not as common. Stock should be, since it is so delightfully fragrant. Both nasturtium and alyssum bloom nicely through either summer or winter, depending on when they started to grow from directly sown seed. Some fibrous begonia can perform through winter if sheltered from frost.

Most color does well from cell packs. Nasturtium should only grow from seed. Chrysanthemum and cabbage might be better from four inch pots. Cyclamen may only be available in four inch pots.

Snails, Weeds And Falling Leaves

Gardening does not slow for autumn.

The coloring of foliage is a bit slow this autumn. The cooling nights after such warm weather is bringing some of the deciduous foliage down while it is barely yellowing. Honeylocust and black oak have already gotten notably sparse without much notable color. Hopefully, the more colorful sweetgum, flowering pear, pistache and gingko trees will retain their foliage later into cooler weather, so that they can put on a worthy show before filling compost piles.

It is probably slightly too early to clean gutters and downspouts. Unless the rainy season somehow starts first, this should probably wait until most of the foliage that is expected to fall has already fallen. Lawns, certain ground covers, decks and pavement should be raked as needed though. Decks and pavement can get stained from the tannins that leach from decomposing foliage. Lawn and ground cover do not like the shade under the debris.

However, slugs and snails really dig the mess. Fallen foliage keeps the ground cool, damp and shaded. Raking leaves does not eliminate slugs and snails, but inhibits their proliferation. There are always plenty of other hiding places. As the weather eventually gets cooler and damp, snails that stay out in the early morning should be collected and disposed of. Of course this technique is not convenient for everyone, since most snails hide before the sun comes up. Small slugs hide earlier in the morning and are even more unpleasant to handle.

Once found, neither slugs nor snails are too elusive . . . or fast. Yet, plucking and collecting them is not a fun job. Once collected, no one knows what to do with them. They can be put into plastic bags and disposed of; and will eventually succumb. Some people prefer to simply toss them onto a dry and sunny driveway or roof where they succumb more quickly and get taken by birds. Snails may need to be squashed to limit mobility.

Even though it is too late to prevent most types of weeds from dispersing their seed, a few types continue to disperse seed as they deteriorate through autumn and winter. Weeds in areas that get watered last longer and disperse their seed later than those without watering. Perennial weeds that are still green in dry areas areas will be easier to pull after the first rain.

Autumn Color From Deciduous Foliage

Deciduous foliage can get delightfully colorful.

Autumn does not get cool enough locally to prevent everything from blooming. A few plants can bloom sporadically all year except only during the coolest part of winter. A few plants naturally bloom in autumn. Cool season annuals begin blooming before warm season annuals finish. Flowers can potentially provide plenty of autumn color if necessary. A mild climate can be a major advantage.

It can also be a disadvantage. Minimal chill causes deciduous foliage to start to get messy before it starts to get colorful. Some deciduous plants shed completely before getting chilled enough to develop appealing autumn color. A few others do not even get cool enough to defoliate completely. They instead retain their shabby old foliage through winter until new foliage replaces it in spring.

Nonetheless, several adaptable deciduous plants get sufficient chill to develop impressive autumn color here.

Sweetgum, Chinese pistache, flowering pear and ginkgo are likely the four best deciduous trees for autumn color locally. Sweetgum and Chinese pistache produce the most impressive ranges of vibrant colors. Flowering pear is comparable, but with less yellow, and more rich deep burgundy red. Ginkgo lacks such range of color, but develops the brightest and clearest yellow autumn color.

Boston ivy, crape myrtle and persimmon get about as colorful as sweetgum, even if incidentally to their primary duties. Crape myrtle is popular for its abundant and richly colorful bloom in summer. Persimmon is a fruit tree. Boston ivy obscures graffiti and helps muffle sound on freeway soundwalls. Cottonwood and black walnut turn bright yellow, but in the wild rather than in refined gardens.

Even for the locally mild climate, there are plenty of deciduous plants that provide foliar autumn color. Trees are the most familiar. Vines and shrubbery are also popular. Because this mild climate is marginal for some of them, color is likely to be variable from year to year. Unfortunately, some that perform satisfactorily for inland locations may perform less satisfactorily in coastal conditions.

These Bulbs Are Not Incandescent

Bulbs do not look too impressive.

It may seem to be too early to be concerned with narcissus, daffodil and grape hyacinth, but this is when their bulbs go into the garden. Once established, these familiar examples, as well as early bearded iris, can be the most reliable for colorful bloom at about the same time early each spring. Crocus and freesia bloom just as early, but may not naturalize as reliably. Lily, tulip, hyacinth, anemone and ranunculus really prefer cooler winters to bloom reliably after their first spring, even though they are worth growing for just one season.

Bulbs, including corms, rhizomes, tubers and tuberous roots, can be found in nurseries when it is time for them to be planted. Gladiolus are not yet available only because they are summer blooming bulbs that should be planted a bit later than spring bulbs. None of the bulbs are much to look at while dormant, and are even less impressive once they get buried out of sight, but they have already stored up everything they need for the blooms that we expect from them next year. Once hidden below the surface of the soil, seemingly dormant bulbs secretly disperse their roots into the surrounding cool and moist soil to be ready to bloom as soon as weather allows.

In their first year, some bulbs can be planted in groups at different times to coincide with the expected durations of their particular bloom cycles. For example, if the flowers of a particular type of bulb can be expected to last two weeks, a second phase of the same bulbs can be planted two weeks after the first phase. As the first phase finishes bloom next spring, the second phase should begin bloom. However, phasing is only effective for the first season, since all bulbs of any particular variety will be synchronized by their second season.

Anemone, ranunculus and bearded iris each bloom synchronously, regardless of when they get planted, so are immune to phasing. Fortunately, the many varieties of bearded iris have different bloom seasons. Some bloom as early as narcissus. Mid-season varieties bloom shortly afterward, and are followed by late varieties. Some modern varieties bloom early, and then again after the late varieties!

Spring Bulbs Begin In Autumn

Spring bulbs bloom months from now.

Spring bulbs lack immediate gratification. They will, of course, justify their habitation of the garden as they bloom next spring. For now, they are not much to look at, and do not stay visible for long. While dormant, they poses neither foliage nor significant roots. Most look something like small and disfigured onions. Burial in shallow graves conceals their uninteresting exteriors through winter.

Cool season bedding plants can effectively obscure the otherwise bare soil over the grave sites of some types of bulbs. Mulch might be best for those that should start to grow immediately or that will develop an abundance of foliage. While plants above them may need watering until the rainy season begins, dormant spring bulbs need no more attention. They disperse roots through winter.

Spring bulbs, including corms, rhizomes, tubers and tuberous roots, are oblivious to the discomforts of transplant while dormant. However, they want to wake from their dormancy in situations that are conducive to normal development and bloom. Some prefer shallow planting. Others require significant depth for stability. Most but not all spring bulbs perform best in small groups or colonies.

Narcissus, daffodil and crocus are the first spring bulbs to bloom as winter ends, or even earlier. Tulip, hyacinth, grape hyacinth, freesia, anemone, ranunculus and some types of iris bloom shortly afterward. Late iris, lily and montbretia bloom later, and some types are considered to be summer bulbs. Spring bulbs become available in nurseries while seasonable. Summer bulbs arrive later.

Most spring bulbs bloom only once. Plaiting them in phases a few weeks apart within their respective seasons can prolong bloom. Each subsequent phase begins bloom as the preceding phase finishes. However, narcissus, daffodil, grape hyacinth and others that can naturalize will bloom simultaneously after their first season. Most spring bulbs unfortunately do not naturalize reliably here.

Gladiolus and allium are summer bulbs that bloom once. Calla, canna and dahlia bloom through summer.

October Brings Cool Season Annuals

Warm season annuals are now passe.

As the name implies, ‘annuals’ need to be replaced ‘annually’. What is worse is that they do not even function for an entire year, but only for a specific season. Cool season annuals mostly work from autumn to spring. Warm season annuals mostly work from spring to autumn. Calendula is a popular cool season annual that may not last even that long, since it can mildew half way through winter.

Now that it is time for cool season annuals, it can be unpleasant to remove warm season annuals that are still performing well. In mixed plantings, new annuals can be phased in through autumn as older annuals deteriorate. Busy Lizzie (impatiens), wax begonia and other warm season annuals that are actually perennials can get cut back and overplanted with cool season annuals. The cool season annuals that temporarily overwhelm them can provide shelter from frost. As the cool season annuals finish next spring, the warm season ‘annuals’ can regenerate

However, not all cool season annuals need to finish next spring. Sweet William, cyclamen, chrysanthemum and the various primroses are popular cool season annals that are actually perennials. When the time comes, they can be overplanted with warm season annuals, so that they can regenerate the following autumn. In cool spots, sweet William and some primroses can actually perform all year. (Some people are allergic to primroses like poison oak.)

Alyssum and nasturtium really are annuals, but can function both as warm season and cool season annuals. They sow their own seeds so that new plants can reliably replace old plants without being noticed. The old plants only need to be pulled as they deteriorate. Alyssum is white, or pastel hues of pink or purple. Nasturtium is just the opposite, with bright hues of yellow, orange and red, with only a few pastel options.

Pansies and smaller violas are the two most popular of cool season annuals, since they function like petunias for cool weather. They lack few colors. Most have two or three colors. Ornamental cabbage and kale produce big and bold rosettes of pink, white or pink and white foliage. Kale has weirdly distinctive foliar texture. White, lavender, pink, purple and rose stock is the most fragrant of cool season annuals, and taller varieties are great for cutting. Iceland poppy has delicately nodding flowers on wiry stems. They can be pastel hues of white, pink, yellow, orange or soft red.

Deciduous Trees Defoliate Through Autumn

Too many fallen leaves get messy.

September 22 was the equinox. Here in the Northern Hemisphere, days will get slightly shorter as nights will get slightly longer. The intensity of the sunlight will diminish as the sun moves farther to the south. The weather will of course get cooler. In this particular climate, the rainy season will begin. Deciduous plants, as well as some evergreen plants, will respond accordingly to the changes.

Deciduous plants defoliate as they go dormant for part of the year. A few defoliate through hot and dry summer weather. Otherwise, almost all deciduous plants defoliate for dormancy through cool and stormy winter weather. They are more resilient without foliage that is sensitive to both frost and wind. While days are short and sunlight is diminished, foliage would not be very active anyway.

The foliage of many deciduous plants gets remarkably colorful during defoliation. Sweetgum, pistache and ginkgo are famously colorful. However, many deciduous plants, such as valley oak and silver maple, are not impressively colorful. Regardless, all deciduous plants that defoliate for winter will eventually start to do so, or have started already. Several evergreen plants shed debris too.

Gravity is a force that is more reliable than weather. It pulls foliar debris downward onto roofs, roadways, decks, patios, lawns and whatever happens to be below deciduous trees.

The timing of defoliation is ironic. Gutters and downspouts that were empty all summer now collect debris as the rainy season begins. They may need cleaning more than once if deciduous trees above defoliate slowly. While patios and decks get less use, they need more raking to avoid staining. Fallen leaves promote rot in turf grass and ground covers, and inhibit penetration of sunlight.

At this time of year, it is difficult to believe that evergreen trees are generally messier than deciduous trees. Deciduous trees tend to defoliate only once annually, although some drop bloom or fruit separately. Evergreen trees drop about as much debris, but do so for a longer season or continuously throughout the year.

Pumpkins Exemplify Ripening Winter Squash

Winter squash are replacing summer squash.

Zucchini is probably the most reliable of warm season vegetable through summer, even when tomatoes are having a bad year. A single zucchini plant produces enough for a household. Two plants produce enough to share with neighbors. Pattypan, crookneck and other varieties of summer squash may not be quite as reliably productive individually, but can be assembled as a delightfully variable team that produces early in summer, and is just now finishing.

The fruit of summer squash is best when immature and tender. It gets tougher and loses flavor as it matures. Because development of seed within maturing fruit exhausts resources, plants are actually more productive if the fruit gets harvested while immature. In other words, they can either make many small fruits, or a few large fruits. The plants have coarse foliage on big but relatively confined annual plants.

Winter squash is very closely related to summer squash. The shabby annual vines sprawl over much larger areas, and can even climb fences and shrubbery. The main difference though, is that each plant produces only a single fruit or only a few individual fruits that are allowed to mature completely through summer. Their ripening fruit is just now becoming available as summer squash are running out. The fruit is supposed to be best after frost has killed the foliage, which could take a while here.

Hubbard, acorn, turban, spaghetti, kabocha and butternut squash, as well as the many varieties of pumpkin, are the more popular types of winter squash. Unlike summer squash, winter squash can be stored for quite a while, and need to be cooked to be eaten. While winter squash do not produce as many fruiting female flowers as summer squash produce, they seem to make at least as many male flowers that can be harvested while still fresh.

Male flowers can be stuffed, battered and fried, or simply fried. After they have been pollinated and set fruit, female flowers are typically too wilted to be eaten. All squash produce more male flowers than female flowers. Even the most fruitful of summer squash produce about three times as many male flowers as female flowers.