European white birch, Betula pendula, is a team player. It usually inhabits landscapes in groups rather than singly. Some trees have two, three or more trunks. After all, its primary allure is its strikingly white trunks. Because its foliar canopies are not overly broad, a few can fit into limited space. It is an informal and relaxed tree with nicely pendulous growth.
Mature European white birches are not much more than fifty feet tall here. They can grow taller where winters are cooler. Their slender trunks are mostly less than a foot and a half wide. They generally lean with prevailing winds and away from shade. Their smooth and white bark develops rough and black furrows with age. Their little leaves are deciduous.
European white birch appreciates regular irrigation, so should perform well within lawns. It produces only moderate shade. ‘Laciniata’ has intricately lobed foliage and a narrower form. ‘Youngii’ is so pendulous that it needs staking to stand upright. It can not grow very tall. ‘Purpurea’ has bronzed foliage and somewhat tan trunks, but has become very rare. European white birch might self sow.
It is looking a bit more like autumn as a few more species respond to cooling weather by discoloring or deteriorating before defoliation.
1. Hosta plantaginea, hosta is really looking shabby now. Actually though, it never really looked all that good. The difference is that this shabbiness is because of cooling weather.
2. Plectranthus scutellarioides, coleus, which looked so splendid for Six on Saturday two weeks ago, is beginning to succumb to cooling weather, as is typical for this time of year.
3. Acer palmatum, Japanese maple, which was still green for Six on Saturday two weeks ago, is now beginning to yellow in response to cooling weather, as it should for autumn.
4. Acer palmatum ‘Bloodgood’ Japanese maple was already bronzy red, but is beginning to turn a bit brighter red because of the cooling weather. Its color may linger for a while.
5. Metasequoia glyptostroboides, dawn redwood is likewise beginning to yellow because of cooling weather. It eventually turns brown while all the other redwoods remain green.
6. Rosa, carpet rose is the only one of these six that is not responding to cooling weather as it produces a few rose hips. I did not expect this. Rose hips are rare in our landscapes.
It lacks the spectacular spring bloom of the other deciduous fruit trees, but compensates. Persimmon, Diospyros kaki, performs double duty with fall color. Its autumn foliar color is impressively fiery orange. Then, it defoliates to reveal plump, abundant and comparably fiery orange fruit. So, it is spectacular with both autumn foliar color and autumn fruit color.
Persimmon trees are tempting. Some cultivars can grow twenty feet tall to become small or even mid sized shade trees. However, if they do so, much of their overly abundant fruit is unreachable. Aggressive and strategic pruning limits their production with most of their fruit in reach. Although undemanding otherwise, this major dormant pruning is important.
Persimmons are self fruitful without a pollinator. However, they supposedly provide more fruit of better quality with another cultivar. Fruit is unfortunately inedible before thoroughly ripe, but then all ripens simultaneously. That is an incentive to share with neighbors and friends. With a bit of effort, fruit is conducive to drying and freezing, although not canning. Ripe fruit is very perishable.
Autumn foliar color gets messy. It is spectacular while suspended in deciduous trees and even on the ground. The problem is that it mixes with wind and rain as it deteriorates and gets sloppy. It necessitates raking from lawns, ground covers and hardscapes. It requires removal from gutters, or eavestroughs, and where it accumulates on roofs. It gets messy.
The timing could not be worse. The wind and rain that cause it to be so messy are no fun to work in. Using ladders to clean gutters and roofs is more dangerous in wet conditions. Fallen leaves are messier and heavier while wet. Yet, they are not too heavy for winds to blow green waste piles about after raking. Autumn weather will get progressively worse.
Unfortunately, gutters that accumulate fallen foliage require cleaning to function properly. Otherwise, foliar debris clogs them and their downspouts when they are most necessary. Rain water then flows over their edges and onto the ground below. It can be more than a minor annoyance. Splattering water can cause rot within adjacent walls that it dampens.
That is why old historic houses originally had ‘foundation plantings’ of dense vegetation. Some lacked gutters because gutters were very expensive. Instead, rain was allowed to flow from eaves and directly onto the ground. Dense vegetation between the dripline and the foundation contained the splattering. Almost all modern homes, though, have gutters.
Gutters may need cleaning more than once before deciduous trees defoliate completely. Evergreen trees necessitate cleaning as well, but do not shed so profusely for autumn. A few, such as redwoods and pines, are exceptionally messy. Because their mess may not coincide with autumn, cleaning it can be a bit earlier. It is easier during pleasant weather.
Cleaning gutters is a gardening task that may be best to leave for professionals. After all, it may involve climbing to unsafe heights on ladders and roofs. Installation of screen like devices over gutters can mitigate the need for future cleaning. Of course, gutters that are not below messy trees might never need cleaning. There are many variables to consider.
Chinese pistache, Pistacia chinensis, does not need too much chill to begin to turn color. In some climates, it is already yellowing. With cooler weather, it will develop fiery orange and red foliar color. Not only does it color reliably with mild weather, but it actually retains its color better. It could defoliate more efficiently within frostier, windier or rainier weather.
Chinese pistache grows about thirty feet tall and broad. Old trees can eventually grow to about forty feet tall. Some old trees are female, so can produce annoyingly abundant red berries. Modern trees should be fruitless male cultivars. Pinnately compound leaves are about nine inches long, with a dozen or so leaflets. Leaflets are two or three inches long.
Because of its resiliency, Chinese pistache is among the more popular shade trees here. Established trees do not need much irrigation and can likely survive with none. Frequent irrigation can promote shallow root dispersion, which can damage pavement. Otherwise, Chinese pistache is a good street tree. It merely needs pruning for clearance over roads, sidewalks and driveways.
Cool season annuals are not the only options for home garden color for autumn. Even in mild climates, deciduous foliage eventually notices increasing autumn chill. While some merely sheds, some first develops spectacular autumn foliar color. Such foliage is not as conducive to instant addition to gardens as annuals are. Yet some may already be there.
A few deciduous shade trees and street trees provide the best autumn foliar color. Some are less popular with those who prefer evergreen trees. However, they are quite practical for some situations. Some are less messy than evergreen trees. They only seem messier because they defoliate so much at once. Most evergreen trees shed throughout the year.
Sweetgum, or liquidambar, probably provides the most colorful autumn foliar color. It also happens to be among the messier deciduous trees. That is because it retains its colorful foliage later into autumn and winter. While prolonged mess is a disadvantage, prolonged foliar display is an advantage. It is an unwieldy large tree, though, with aggressive roots.
Chinese pistache is as colorful, with dazzling yellow, orange and red autumn foliar color. It seems a bit less messy because it defoliates a bit sooner. Also, it does not produce the spiky seed capsules that sweetgum trees produce. However, its smaller leaves require a bit more effort to rake than larger leaves. Chinese pistache is a rather popular street tree.
Flowering pear, or callery pear, produces similar autumn foliar color, with more deep red. It also provides billowy white spring bloom. Crepe myrtle is a smaller tree with both vivid autumn foliar color and summer bloom. Ginkgo is a tall and slender tree with exclusively brilliant yellow color. Boston ivy is a clinging vine that is as colorful as Chinese pistache.
Not all deciduous trees produce impressive autumn foliar color. Sycamore might already be defoliating with just a bit of pale yellow color. Valley oak does the same later. Both are quite messy as they defoliate slowly through much of autumn. However, both are notably sculptural while bare later through winter. There are other advantages to deciduousness.
Both work and home gardening were relatively mundane this week. Consequently, these six lack a theme. Irrigation is at that awkward phase when less is necessary, but it is still very necessary. No more rain came after the first storm of the season, but the weather is cooler, and the days are shorter. Autumn is arriving . . . slowly. Maybe I will get pictures of autumn foliar color for next Saturday.
1. Robinia pseudoacacia, black locust is much more out of focus than I was aware of as I took this picture to show how blue the sky is without any rain in the foreseeable forecast.
2. Begonia X semperflorens–cultorum, wax begonia succumbed to a major infestation of fungus gnat larvae. These fresh cuttings were made from their unaffected upper growth.
3. Amaryllis belladonna, naked lady seedlings grew from seed from white flowers. They will not bloom for several more years. I am curious to see if they might also bloom white.
4. Saccharum officinarum, sugarcane probably should not have been bothered until the end of winter, but I separated five clumps. This is the traditional Purple Ribbon cultivar.
5. Acer rubrum, red maple is redundant to a picture of the same two Saturdays ago, but is too pretty to not get a last picture of before the end of its season. It is mostly bare now.
6. Rhody was busy with relaxation while I was at work on Thursday. He is commendably proficient with such tasks, while not being late for petting sessions and treats afterward.
Red maple colors nicely, but the color does not last for long.
Spray paint is no way to get good autumn color in the garden. The healthy rich green king palm out front would look ridiculous and be very embarrassed, not to mention unable to breath, if it were painted yellow, orange and red, like the sweetgum trees that will soon be getting so colorful in the neighborhood now that the weather is getting cool.
Just like every other feature in the garden, autumn foliar color takes proper planning. Most of the plants with the most impressive autumn color happen to be substantial trees, so are not as easy to accommodate in as many situations as flowering annuals are. There are a few smaller shrubby plants and perennials that provide autumn foliar color, but almost all are deciduous, so defoliate to leave bare branches through winter.
Boston ivy (which is not really ivy) is probably the most colorful of climbing vines. It is a bit too aggressive for small spaces though, and damages painted surfaces and just about anything that it gets a hold of. It is best on concrete walls, which is why it is so prominent on freeway soundwalls and overpasses. Grapevine and wisteria are only moderately colorful.
Currant, crape myrtle, pomegranate, smoke tree and redbud are a few of the shrubby plants that provide good color in autumn. Crape myrtle and Eastern redbud are actually more commonly small trees. Many of the Japanese maples with good autumn color are small trees that stay smaller than most shrubbery.
Sweetgum, Chinese pistache, flowering pear and maidenhair tree are the best trees for autumn color, though maidenhair tree turns only bright yellow without the oranges and reds that the others get. Where well exposed, Japanese persimmon is comparable to Chinese pistache. Fruiting pear, apple, apricot, plum, prune and almond trees are not quite as colorful.
Several of the North American and European maples are remarkably colorful, but do not hold their foliage as long as sweetgum does. Silver maple and box elder (maple) happen to be less colorful than the other maples. Various poplars and locusts, as well as tulip tree and black walnut can almost get as bright yellow as maidenhair tree does.
Autumn foliar color is scarce here, not because the weather is too mild, but because it is not such a priority within landscape design. A few species can develop such color as they do where autumn weather is cooler. Of course, some do not. Native California sycamore is a stately deciduous tree with striking form while bare through winter, but contributes minimal color.
1. Cornus florida, flowering dogwood is just beginning to exhibit foliar color for autumn. It performs surprisingly well in the Santa Cruz Mountains above the Santa Clara Valley.
2. Lagerstroemia indica, crape myrtle is also starting to exhibit foliar color for autumn. It may do so before the weather gets cool, as if it somehow knows what time of year it is.
3. Platanus racemosa, California sycamore does not know or care what time of year it is. It is more likely to yellow in response to hot and dry summer weather than to do so now.
4. Platanus X acerifolia, London plane tree is the sycamore with maple foliage. It is just beginning to yellow, but ultimately, does not do much more than that before defoliation.
5. Acer platanoides, Norway maple is the maple with sycamore foliage. This cultivar has bronze foliage through summer, so develops its yellow foliar color for autumn quite late.
6. Acer rubrum, red maple, like crape myrtle, can develop foliar color for autumn before cool weather, as if it knows what time of year this is. It defoliates relatively early though.
Pistache does not need much chill to develop exquisite foliar color.
Cooler climates may not have so much annual flower color to choose from at the end of summer, but have more autumn color from trees and a few shrubs and vines. The weather is of course different every year, so autumn color is never predictable. Just as some of the typically colorful trees may not be so spectacular every year, some of the more mundane trees may be surprisingly colorful if the weather is just so.
In milder climates, sweetgum (Liquidambar), flowering pear and Chinese pistache are generally the most reliable for the most color as the weather gets cooler. All three exhibit a good range of color, from clear yellow, through orange and bright red. Sometimes, particular colors are more prominent, or even exclusive. For example, Chinese pistache can be completely orange without yellow or red. Some cultivars of sweetgum specialize in particular color ranges. For example, ‘Burgundy’ turns dark red or purplish red without much yellow or orange.
In cooler climates, maples color well. Sugar maple is perhaps the most colorful, comparable even to sweetgum. Unfortunately, it does not hold onto its foliage as tightly, and soon looses it to slight wind or rain. Red maple colors just as reliably, but is more red and brown with less yellow and orange. Norway maple typically turns yellow or somewhat orange. Silver maple turns only dingy yellow, but gets big enough to make quite a show.
The best bright yellow is probably provided by maidenhair (Ginkgo biloba) tree. Birch, honey locust, tulip tree, fruitless mulberry, some willows and poplars can be comparable if the weather turns cool suddenly. Redbud, dogwood, hawthorn and flowering cherry are more subdued shades of yellow, but are grown more for their spring flowers anyway. Persimmon probably provides the best brightest orange foliage, followed by abundant and comparably bright orange fruit!
Some ash, some oaks, Chinese tallow tree, parrotia and dawn redwood all provide their own flavors of autumn color. Dawn redwood and pin oak actually turn simple brown, which some people think makes the trees look dead! Raywood ash turns a nice burgundy red or purplish. However, the old fashioned Modesto ash (which is a type of Arizona ash) turns as bright yellow as fruitless mulberry does. Not all crape myrtles have good fall color, but some are as colorful as sweetgum is. Various hazels, spiraeas and viburnums are colorful shrubbery in autumn. Wisteria vines, which are known more for their colorful spring flowers, turn yellow.
Tony Tomeo 