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Evergreen Trees Drop Leaves Too

IMG_20141004_153228As the deciduous trees that will soon be coloring for autumn defoliate for winter, the evergreen trees will become more prominent. Some evergreen trees will drop some of their foliage along with deciduous trees through autumn and winter. Many drop some of their old foliage as new foliage develops in spring, or later in summer. All are on distinct schedules, but are never completely bare.

That certainly does not mean that evergreen trees are not messy. To the contrary, some happen to be significantly messier than some deciduous trees are. They are only evergreen because they do not drop their old foliage until it is replaced by new foliage. Whether individual leaves last just slightly longer than a single year, or for several years, they eventually shed and fall to the ground.

In fact, evergreen trees may shed small but pestering volumes of foliage for a few months or even constantly throughout the year. Some deciduous trees defoliate so efficiently within a very limited time once the weather gets cool, that all of their fallen leaves will be raked away within only two or three weeks. Of course, some trees, both deciduous and evergreen, drop flowers or fruit or both.

Not only do most evergreen trees shed for a longer time than most deciduous trees do, but most shed foliage that is not so easy to rake away. Cypress shed minute and finely textured leaves that are impossible to rake from lawns, but toxic if they accumulate. Juniper and arborvitae are easier to accommodate only because the trees are smaller. Fir, spruce and cedar have bigger needles.

Broadleaf evergreen trees are very different from coniferous trees. Their leaves are considerably easier to rake. They are generally more substantial than those of deciduous trees though. Some may not decompose so readily in deep groundcover. Southern magnolia leaves are notably slow to compost. Instead of producing cones, some broadleaf trees drop acorns or other messy seed.

Nonetheless, where there are compatible with their landscapes, evergreen trees are as practical as deciduous trees are.

Posted on by tonytomeo · 5 Comments

Slow Color

P91110Autumn is not much to brag about here. It supposedly got just cool enough at night for the minimal requirement of frost, at 32 degrees, but no one noticed. It has been getting to the low 80s during the day. There has been no rain yet, and none is in the forecast. As bland as such weather seems, it is not at all out of the ordinary. Autumn often arrives later than it does elsewhere.

Consequently, autumn foliar color is not much to brag about either. There are only a few trees that reliably develop good color, such as sweetgum, pistache, flowering pear, crape myrtle and maidenhair tree (ginkgo). As reliable as it is, maidenhair tree provides only bright yellow, without the oranges and reds that the others exhibit. None are exhibiting significant color just yet.

There are several other trees that have potential to develop good color, but are not as reliable about doing so. Birch can get almost as brilliant yellow as maidenhair tree does, but does not do it every year. Red oak may turn brilliant orange with a bit of brownish red mixed in, but only every few years or so. On rare occasion, even London plane (sycamore) shows off burnt orange.

Every species has a distinct personality. They each respond differently to different variables. Weather conditions that stimulate good color among flowering cherries may not stimulate good color for bigleaf maples. Dogwoods that colored so well at about the same time last year as the tulip trees, are already nearly bare after minimal color, while the tulip trees are mostly green.

Every few years, if mildly but suddenly chilled, these cottonwood develop a brighter yellow, with less blotching. With slower and drier chill this year, they are deteriorating and falling without much yellow at all.P91110+

Posted on by tonytomeo · 25 Comments

Buckeye

P91109KCalifornia flora is remarkable. It all does what it must to live comfortably in every ecosystem, climate and geographical region here.

California horsechestnut or California buckeye, Aesculus californica, is one of the more unusual native species. It is so in tune with the climate that it makes other deciduous trees seem to be inexperienced. Of course, to those who are unfamiliar with it, it just looks dead right now.

In chaparral climates of California, some deciduous trees start to defoliate early, before the weather starts to get cool in autumn. California sycamores, for example, can start to defoliate late in summer if the weather gets too warm and dry for them to want to hold their foliage any later. Such defoliation is more the result of minimal humidity than the result of chill.

California horsechestnut takes this technique one step further, by shedding spring foliage even earlier in summer, then refoliating once the rain starts in autumn, and then defoliating again as the late autumn foliage succumbs to frost through winter. It is ‘twice-deciduous’. It is a weird process that should not work, but obviously does.

It seems like a tree that is defoliated most of the time would exhaust its resources and wear itself out. However, California horsechestnut somehow stores enough resources to produce weirdly big seeds. These in the picture above are the same that were featured in ‘Six on Saturday‘ last week, while they were still in their husks.

Squirrels might chew on a few of these seeds, but do not bother storing them. They are mostly ignored by wildlife, perhaps because of their objectionable flavor. So, without squirrels to bury them, they fall to the forest floor near the trees that produce them, where they are too bulky to sift through the detritus to reach the soil below.

It makes one wonder why they put so much of their limited resources into seeds that are too big to reach the soil, but unappealing to wildlife that might otherwise disperse and bury them.

They know what they are doing.

Once the rain starts, and the seed sense that the weather is damp, they germinate on the surface of the detritus on the forest floor, and extend their tap roots through the detritus to the soil below. The seeds are too bulky to reach the soil directly, but contain all that their primary tap roots need to survive without desiccation until they reach the damp soil.

 

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Six on Saturday: Tree Removal

 

The forest is constantly producing trees faster than we can cut them down. Even if we were not too busy with our many other tasks, we are not equipped to safely remove all of the large trees that become hazardous as they mature. Therefore, a crew who is so equipped is sometimes hired, and was here just this last week to remove several locusts, a few bays and a live oak.

1. The 80s are over. Someone painted this water pipe like this so that a crew cutting trees down nearby would not drop anything on it. The crew would have just put an orange cone over it.P91109

2. I was much younger and healthier back in the summer of 1988, when I did an internship with some of the most excellent arborists in the Santa Clara Valley, but I never climbed like this.P91109+

3. These trees are not much more than eighty feet tall, but needed to be parted out over those roofs. They are less than forty years old, from the 1980s or so. The arborist is in the middle.P91109++

4. Locust is unpopular firewood. These locust trees were therefore cut into logs less than seven feet (or 84 inches) long to fit into a pickup for removal, but were then instead chipped on site.P91109+++

5. This structurally deficient oak will eventually need to be removed. For now, it is groomed and lightened for winter storms. It was a nice day at the time, with temperatures in the low 80s.P91109++++

6. Mature bay trees develop distended lignotubers. The trunk of this bay tree was significantly narrower just two feet above this stump. The tree was not much more than eighty years old.P91109+++++

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/

Posted on by tonytomeo · 1 Comment

Red Willow

P91108It is almost never planted in home gardens, but the native red willow, Salix laevigata, has a sneaky way of getting where it wants to be. The minute seeds go wherever the wind blows them. Because it is a riparian tree, red willow prefers well watered spots. If not detected and pulled up in the first year, it can grow rather aggressively, and overwhelm more desirable plants, although the somewhat sparse canopy makes only moderate shade.

With a bit of grooming, red willow can be a handsomely asymmetrical tree, with upright branch structure. However, even the healthiest trees rarely get more than thirty feet tall, or much more than forty years old. The leaves are a bit shorter and wider than those of the more familiar weeping willow, and do not color as well in autumn. There are actually a few other native willows that are also commonly know as red willow. Some are quite similar, while others are very different.P91108+

Posted on by tonytomeo · 4 Comments

Why Autumn Is Also Fall

50923thumbNow that leaves are falling, they need to be raked. Large leaves, like those of sycamore and fruitless mulberry, can shade out lawn, shallow ground cover or dense shrubbery. If shade is not a problem right away, mildew can be after only a bit of rain. If abundant enough, finely textured silk tree or jacaranda foliage that typically sifts harmlessly through shrubbery and most ground cover, can accumulate and damage lawn, dichondra and the densest of ground cover. Walnut foliage has an herbicidal effect on sensitive annuals and some perennials.

Foliage is only beginning to fall. Cooling weather causes deciduous trees to shed more. Rain and wind bring the foliage down even faster. Even evergreen trees that naturally shed throughout the year will likely shed more through the upcoming wintry weather. Some trees start to defoliate early in autumn. Some hold their foliage until frost. Some trees that seem to be evergreen hold their foliage through winter, and then only drop their older foliage as it gets replaced by new foliage as winter ends.

Pavement and decks should be raked of leaves, not only to avoid staining, but also because rotting leaves can become dangerously slippery. Curbside gutters are too visible to get neglected for too long. However, heavy rain can quickly deliver to the cleanest of gutters a mess of fallen leaves as well as any other debris and litter that happens to be up the road. Strong wind can be filtered through hedges, leaving drifts of blowing leaves.

Leaves should also be cleared from roof gutters and downspouts, and may need to be cleared away again later in the season. More debris may need to be removed from awkward spots where it might accumulate, such as behind chimneys. Flat roofs may need to be raked.

There are a few exceptions to the need to rake fallen leaves. Where they get absorbed into coarse ground cover like Algerian ivy, falling leaves are generally not a problem. Pine needles and cypress foliage can be left if it happens to be useful for the natural suppression of weeds. Mature coast live oaks and valley oaks that are accustomed to a layer of their own fallen leaves over the surface of the soil actually want it to stay. For them, the foliar debris is a mulch that adds organic matter, insulates the soil, and retains moisture.

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Horridculture – Sealant

P90810++++Grafting compound is a thick sealant applied to a fresh graft union to limit desiccation while the graft knits. A bit more typically gets applied to the cut distal end of the scion. There are various formulations of grafting compound, ranging from something resembling roof patch to a something with the consistency of thick paint.

The stuff, as sloppy and icky as it is, really is helpful. I can not imagine how big orchards were grafted before it was invented.

It is also useful for keeping cane borers out of the cut ends of freshly pruned roses. For those of us who remember how to prune roses properly, leaving only a few thick canes, grafting compound really is practical. I just don’t use it on roses because cane borers are not a problem here.

Since I do not use grafting compound on roses, and the plants that I graft do not need grafting compound, I presently have no use for it. I suppose I could use it on apple and pear trees, but it really is not necessary. When I get around to grafting apricots and peaches, it will only be for a few trees in my own garden, so I will just use candle wax.

This surprises people. At work, I am often asked about ‘painting’ pruning wounds and shiners as trees get pruned, presumably with sealant. Decades ago, it was actually commonly done. Even when I did my internship in arboriculture in 1988, some arborists were applying sealant because it was easier than arguing with their clients about it not being necessary.

The problem with applying sealant to large wounds is that is actually seals moisture within the otherwise exposed wood, and promotes rot. It is best to do nothing, and allow the affected trees to compartmentalize their wounds as they would do naturally if limbs were broken off by the weather. Trees know more about their processes than we do.

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Leyland Cypress

91113The ‘X’ preceding its Latin name ‘X Cupressocyparis leylanii‘ designates Leyland cypress as a hybrid of two distinct genera, namely Monterey cypress and Nootka cypress. (Those who consider the parents to be two species of the same genus know Leyland cypress as Cupressus X leylandii.) The many cultivars combine desirable qualities of both parents, but also innate weaknesses.

Rows of Leyland cypress grow fast to become densely evergreen windbreaks or informal screens within only a few years. However, they are very susceptible to cypress canker, and are likely to succumb within twenty five years or so. Farther inland, they may not last half as long. That may be quite acceptable for temporary windbreaks in front of slower but more permanent shrubby trees.

Common Leyland cypress develops a distinctly plump but conical form, with slightly grayish foliage. Most other cultivars are more columnar. Foliar color ranges from bluish green to gold. The tiny scale leaves are densely set in flat sprays. Healthy trees can get nearly thirty feet tall in ten years. Most stay lower where exposed. Crowded trees that live long enough exceed a hundred feet tall.

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Mulch Is Imitation Of Nature

91113thumbEvery living thing in our gardens came from the wild somewhere. A few plants might be natives trying to adapt to synthetic landscapes. Some might be from similar climates. Some are likely from very different climates. Even houseplants came from the wild somewhere in the World. Regardless of their respective origins, in home gardens, all plants want to behave as they would in the wild.

Many plants want to defoliate at this time of year. Even some evergreens want to shed some of their old foliage before winter. Some perennials die back to the ground. Most summer annuals are already dead. There is an abundance of deteriorating organic material getting discarded by the plants that produce it. In the wild, all this detritus would naturally fall to the ground and decompose.

That might be a problem in parts of our refined landscapes. Fallen leaves must be raked from lawns, decks, pavement and various other flat spaces outside. If left too long, they shade out lawns, ground cover and bedding plans. Fallen leaves can stain decking and pavement too. The worst diseases of roses and fruit trees overwinter in fallen infected debris that does not get raked away.

Unfortunately, raking the mess of autumn away deprives the plants that live in the garden of the abundant decomposing organic matter that they expect to be delivered this time of year. The soil is left exposed and uninsulated, allowing temperature and moisture content to fluctuate more than they would naturally. Nutrients are not replenished as readily as they would be from decomposition.

Mulch, which can be applied at any time of the year, is quite seasonably appropriate in autumn. This is when plants expect decomposing organic matter to arrive from above. Mulch compensates for the loss of what we consider to be a mess, but what plants consider to be an important component to their natural ecology. It gives them what they want, but is neat enough for refined gardens.

The best mulch for the job just might be fallen leaves that were raked last year and composted, perhaps with other debris from the kitchen and garden.

Posted on by tonytomeo · 21 Comments

The Bad Seed Redemption

P91103The seed is not really bad. At least I do not think that it is. It is merely misunderstood. Perhaps it would be more accurate to say that it is simply unidentified. I really do not know what it is. I do not say that very often, especially about seed that I bother to collect to sow elsewhere. I believe that it is of American bellflower, Campanula americana. If not, it is very closely related.

It appeared in part of one of the landscapes at work. Because it looked like some sort of campanula, we left it to see what it would do. It got quite tall, but never started to look like something we did not want to take a chance on. We were rewarded for taking the risk when it bloomed with these elegant spikes of small sky blue flowers. That was a little more than a year or so ago.

No one bothered to deadhead it immediately after bloom. It was only a few plants on the back edge of rather relaxed landscape, so was easy to ignore. By the time the dried floral stalks were noticed and removed, the seed had already been tossed. Consequently, there were many more of them through this last season, both in the same area, and in adjacent parts of the landscape.

In fact, there were too many to ignore when their floral spikes had finished blooming. I deadheaded them myself so that I could collect the dried floral carcasses in a small bucket. Some seed had already been tossed for next year. Nonetheless, there is enough dust-like seed in the bottom of the bucket to share with other landscapes. I intend to sow it just prior to winter storms.

So, this unidentified seed should be an asset to the landscapes.