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Warm Weather Confuses Dormant Plants

60217thumbClimate is what makes gardening so excellent here. It is just warm enough in summer for plants that like a bit of heat, but not too unbearably hot for too long. It is just cool enough in winter for plants that like a chill, but not cold enough for hard frost or heavy snow. The climate is also comfortable for us while out in the garden! Yet, even local climate is neither perfect nor predictable.

El Nino is still out there, and likely to deliver an abundance of rain. The rain last month was great while it lasted. This presently dry and warm weather in between has been excellent, but is likely to cause serious consequences. Some deciduous plants that are normally bare through winter are being deprived of adequate dormancy. Some are blooming prematurely, and may foliate soon.

When the rain resumes, it will ruin some of the premature bloom. This is generally harmless for most fruitless flowering trees like the various acacias, flowering plums and saucer magnolias, but compromises their most alluring feature. It can be more dangerous to flowering pears (including evergreen pear) and flowering crabapples, because wet blossoms can be infected with fire blight.

The more serious problem is that rain ruins blossoms and juvenile fruit of various deciduous fruit trees. Stone fruits such as almonds, apricots, cherries, plums, prunes, peaches and nectarines bloom first, and do so with delicate blossoms. If the blossoms do not get knocked off by rain, the juvenile fruit will rot if it stays damp too long. Many fruit trees are likely to lose all fruit this year.

Apple and pear trees should be safer because they bloom later, and bloom with more substantial flowers. (However, like their fruitless relatives, their wet blossoms are very susceptible to fire blight.) Persimmons and pomegranates bloom even later, and with even tougher flowers, so should be safe. Figs are in a league of their own, and should be fine if summer is warm.

Fortunately, destruction of bloom and fruit, although disappointing to us, is harmless to the affected trees.

Posted on by tonytomeo · 3 Comments

Finish Transplanting Before Winter Ends

90220thumbAutumn is for planting; and for good reasons. It is the beginning of dormancy for almost all plants, including evergreens. It precedes cool and rainy weather that inhibits desiccation until new roots are able to disperse sufficiently to sustain new plants. Some plants need to be in the garden in time for winter chill in order to initiate bloom. However, not everything should get planted in autumn.

Winter is the best season for some plants. Many summer blooming bulbs get planted in winter because they are likely to start growing prematurely and get damaged by frost if planted in autumn with spring bulbs. Some perennials that are slightly sensitive to frost may get planted after average frost season so that they can bulk up enough to be more resilient to frost by the following winter.

Besides new plants that are purchased from nurseries to be planted in the garden, there are plants that are already established in the garden that might need to get dug, divided, and then planted back into the garden, or shared with friends and neighbors. Some might need to be transplanted because they are crowded or in the way of something. These present a different set of variables.

Once divided and transplanted, grasses, New Zealand flax, lily-of-the-Nile, African iris and other stoloniferous perennials (that spread by creeping stems known as stolons) are more susceptible to rot than nursery grown plants, because so many of their roots get severed. Even if aggressively pruned while getting divided and transplanted, shrubby plants, like lilac and forsythia, are more susceptible to desiccation than nursery grown plants, simply because they lack sufficient roots.

If divided or transplanted through winter rather than autumn, plants get a few weeks of cool and rainy weather to settle and disperse their roots, but do not have enough time to rot or desiccate before the weather gets warm enough for them to resume growth and recover resiliency. Perennials that get cut back in the process spend less time looking shabby before new growth develops.

Posted on by tonytomeo · 7 Comments

Attack Roses While They Sleep

8bd4This theme may be getting a bit redundant about now. There is just so much that needs to be done in the garden through winter for what will bloom in spring and summer. We plant new fruit trees, and prune mature ones. When we finish planting spring bulbs, we can start planting summer bulbs. Berries, rhubarb and grapes all get planted. With all this going on, it is also time to prune roses.

Like so many fruit trees through the past few centuries, modern roses were bred to maximize production. Instead of big and abundant fruit, they produce big and colorful flowers. Such enhanced production is more than overgrown rose plants can sustain. Pruning eliminates superfluous stems to concentrate resources into fewer but more vigorous stems, and flowers of superior quality.

Pruning also eliminates diseased, damaged, dead and dying stems; which are known as the ‘four Ds’. Foliage falls from the stems naturally through winter, but should be raked and disposed of because it can spread disease to new foliage in the spring. (Dormant fungal spores and bacteria overwinter in fallen foliage.) Foliage that clings to stems after pruning should be plucked away.

Pruning should ideally be done by the time buds begin to swell in late winter. Of course this is not as easy as it sounds in the mild local climate. Buds swell early, and may even start to grow before rose flowers from the previous season finish blooming! Modern ‘carpet’ roses and a few other shrubby types barely go dormant, but fortunately, they do not need such meticulous pruning anyway.

Hybrid tea roses need the most severe pruning, which leaves only three to seven canes approximately two feet high. These canes should ideally be unbranched below where they get pruned, and be spaced somewhat evenly around the center. Stout canes that grew last summer from the base of each plant are best. However, canes below graft unions are suckers that need to be removed.

Floribunda roses are pruned similarly, but can retain a few more canes. Some grandiflora roses are allowed to get significantly taller, with new canes on top of canes from the previous year, which may already be on top of canes from another previous year. It may take a while before they develop replacement canes from the base. Climbing roses likewise retain old canes for a few years.

Tree roses should be pruned as if the upper graft union is at ground level, so that canes should be about two feet high above the graft union. (Although, tree rose canes are usually pruned shorter.) Carpet roses and a few bramble types only need to be pruned low, but cane quality is not so important. They are not grafted, so can not develop suckers.

Posted on by tonytomeo · 3 Comments

Bulbs Are Not Finished Yet

90213thumbIt was easy to forget about spring bulbs after they went into the ground so unceremoniously last autumn. They got buried without so much as proper funerals. Cool season annuals got planted over the grave sites of some, just because bare soil is not much to look at. They stayed silent out in the garden through the cool and rainy winter weather. It might have seemed like the perfect crime.

Now they are back. Daffodil, narcissus, crocus and snowdrop might already be blooming. If not, they are at least extending their vertical foliage. Tulip will be right after them. Spring bulbs tend to bloom in very early spring or late winter here, just in time to remind us that there are even more bulbs and bulb like perennials to plant. This is the time of year for planting summer blooming bulbs.

As the name implies, summer blooming bulbs bloom later than spring blooming bulbs. They also get planted later. Unlike spring bulbs, they do not enjoy winter in the garden. (Most spring bulbs are chilled before sale, but would otherwise need winter chill to bloom in spring.) In fact, some summer bulbs are sensitive to frost if they start to grow too early. Types that bloom only once can be planted late to extend bloom, but will need to be watered more carefully after the rain stops.

Dahlia, canna and the old fashioned big white calla are the easiest of summer bulbs. Happy dahlias can last for years, and can be divided if they get big enough. Cannas are even more reliable and more prolific. Big white callas are slow to get started, but can be difficult to contain of once they get established. However, the smaller colorful types are quite demanding, and not so reliable.

Gladiolus and the various lilies are among the most impressive of summer bulbs, but they bloom only once annually, and if not grown in ideal conditions, are unlikely to bloom more than once ever. Lilies want to be watered and fertilized regularly, and grown in rich potting medium. Gladiolus bulbs are typically planted in groups, but only a few in each group will likely regenerate after bloom.

Posted on by tonytomeo · 6 Comments

Bulbs Now For Summer Bloom

60203thumbLike a timely sequel, bulbs are back. Spring blooming bulbs were available in nurseries earlier, so that they could get planted and disperse their roots through winter, and get ready for their early bloom. Since then, Christmas trees came and went as they were replaced by bare root stock. Now that bare root stock is selling, summer blooming bulbs are arriving for late winter planting.

Summer bulbs are not on the same schedule as spring bulbs. Most of the earliest spring bulb bloom while their foliage is still developing. A few daffodil, grape hyacinth and crocus are already blooming prematurely. Summer bulbs start to grow a bit later and grow a bit slower, and then bloom only after their foliage has matured. Some may not bloom until late summer or early autumn.

There are a few similarities between spring and summer bulbs though. Both groups include plants that develop corms, rhizomes, tubers or tuberous roots instead of bulbs. All are known as ‘bubs’ for convenience. Although very different physiologically, they all function about the same way, by storing resources through dormancy so that they can regenerate within their particular season.

Another similarity is that after spring and summer bulbs bloom, and their spent flowers get pruned away, their foliage should remain until it withers. This foliage is what sustains the bulbs below while they replenish resources to survive through the next dormancy. (Actually, most bulbs replace themselves with new bulbs.) This foliage will want water and fertilizer like any other perennial.

Unfortunately, even with regular watering and fertilizing, the most popular spring and summer bulbs are not really as reliably perennial as they are purported to be. Except for the few types that thrive and naturalize like daffodils (spring) and crocosmia (summer), most bloom very impressively only in their first year, and then bloom meagerly in their second year, if they bloom again at all.

Crocosmia, dahlia, hardy orchid (Bletilla), canna and classic big white calla are the most reliable summer bulbs. Smaller colorful callas are not as easy, but are worth trying. Gladiolus, tuberous begonia and the various lilies are so spectacular that no one minds if they bloom only for one summer. Astilbe, liatris and various alliums work nicely behind where summer annuals will go later.

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Plant Bare Root Plants Properly

90206thumbCompared to canned (potted) nursery stock, bare root plants have a few advantages. They are less expensive, easier to handle, more conducive to pruning into a desired form, and they disperse roots and get established more efficiently. One more advantage that is not often considered is that they are easier to install into the garden. For some, it is as simple as poking a stick in the mud.

Perhaps the only disadvantage of bare root plants is that they must be planted immediately, so that they get their roots soaked and settled into the ground into which they will disperse new roots. If planting must be delayed, roots can soak in a bucket of water for only a few days. Unless they are to live in big pots, potting for a season only delays and interferes with efficient root dispersion.

Only bare root trees that need root barriers (to divert roots from pavement) or mesh gopher baskets (to divert gophers from roots) will need planting holes that are as big as those for canned nursery stock. Otherwise, planting holes need be only as wide as the bare roots, and should be no deeper. If soil is loosened too deeply below, new plants will sink as loose soil settles. Graft unions must remain above grade.

Well flared roots can be spread over a cone of soil formed at the bottom of the planting hole. Conversely, cane berries, after their roots get loosened, can simply be dropped into slots formed by sticking a shovel into the ground and prying it back.

Soil amendments that are useful for providing a transition zone between potting media of canned nursery stock the surrounding soil are not so important with bare root stock. Bare root plants only want a bit of soil amendment if the soil is too sandy or too dense with clay. Otherwise, too much amendment can actually inhibit root dispersion by tempting roots to stay where the richest soil is.

Once planted, trees can be pruned as desired. Most come with superfluous stems to provide more options for pruning, and some stems will be damaged in transport. Fertilizer need not be applied until growth resumes in spring.

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Conifers Have A Woodsy Style

81205Conifers are the most prominent forest trees in North America, but are notably scarce in home gardens. Except for compact varieties of juniper (which were probably too common years ago) and arborvitae, most conifers are trees that get too big for residential gardens, and few adapt to regular pruning that might keep them contained. Almost all are evergreen, so block sunlight in winter.

Gingko (maidenhair tree), bald cypress and dawn redwood happen to be deciduous conifers; but gingko is typically thought of as a ‘broadleaf’ (not coniferous) tree, and bald cypress and dawn redwood are quite rare. The various podocarpuses are useful coniferous trees that happen to be very complaisant to pruning, but like gingko, they are typically thought of as broadleaf trees.

Junipers and arborvitaes are just as practical for home gardens as they ever were, and the many modern varieties that have been introduces over the years are even more interesting than the old classics. Modern arborvitaes are more compact. Modern junipers exhibit more colorful foliage, and more distinctive forms and textures. Foliage can be lemony yellow or blue like a blue spruce.

Simply speaking, conifers are cone bearing plants. They are typically outfitted with needle or scale leaves. Of course, it is not that simple. Juniper seeds are contained in fleshy structures that resemble berries. Gingo and podocarpus seeds actually come with a squishy mess. So, ‘cones’ are not always as easy to recognize as pine cones are. Neither are the wide ‘needles’ of gingko.

Redwoods, pines, cedars, cypresses, Leyland cypresses, spruces and firs are the more familiar of the larger coniferous trees. Bunya bunya, Norfolk Island pine, western red cedar, incense cedar and the various yews and chamaecyparises are somewhat rare. Larch and hemlock are very rare because they do not like the climate here. With few exceptions, these larger conifers have dominant central trunks that can not be pruned down without ruining the structure of the trees as they develop.80516

Posted on by tonytomeo · 10 Comments

Winter Pruning Of Fruit Trees

90130thumbThe vast orchards of the Sacramento and San Joaquin Valleys might make the impression that production of fruit is easy. The trees naturally bloom in spring, and develop fruit over summer, as if they do most of the work prior to harvest. In reality, those trees have been so extensively bred to maximize production that they need, among other maintenance, very specialized pruning in winter.

Without pruning, deciduous fruit trees produce more fruit than they can support. The weight of the fruit breaks and disfigures limbs. Excessive fruit production exhausts resources so that, although more fruit is produced, it is of inferior quality. Diseases and insects proliferate in crowded stem growth that lacks vigor. Unharvested fruit that is beyond reach in upper growth may attract rodents.

Well pruned deciduous fruit tree produce fruit of much better quality, and are able to support it on well structured limbs that are reasonably within reach. They are less susceptible to diseases and insects. Such pruning seems severe to those who are unfamiliar with it, but it is necessary, and the trees appreciate it. Because it is so severe, it is done while trees are dormant through winter.

Different types of fruit trees need distinct types of pruning. Furthermore, different cultivars of each type may need different degrees of the same type of pruning. All should get the ‘four Ds’, which are ‘dead, dying, damaged and diseased’ growth, pruned out of them. Because figs produce early and late crops, they can be pruned less for more early figs, or more severely for more late figs.

Most of the deciduous fruit trees are either stone fruits or pomme fruits. The stone fruits include apricot, plum, prune, nectarine, peach and cherry, which are all of the genus of Prunus. Pomme fruits are apple, pear and quince. Because the winter pruning of deciduous fruit trees is so specialized and so intensive, it is worth studying, preferably before planting the fruit trees that require it.

Posted on by tonytomeo · 16 Comments

Some Plants Impress With Bark

P80805Lemon eucalyptus, ‘Marina’ madrone, cork oak and all sorts of melaleuca trees are known more for their interesting bark than for their foliage or flowers. It helps that their distinctive trunks and branch structures are ideal for displaying their unique bark. Color and texture of bark is remarkably variable, and tends to get noticed more in winter while blooms and foliage are lacking.

Bark of sycamores, birches, elms and crape myrtles that had been so handsome throughout the year is more visible now that it is not partially obscured or shaded by the deciduous foliage that is associated with it. Trunks and limbs of European white and Jacquemontii birches are strikingly white. ‘Natchez’ crape myrtle has distinctively blotched bark, (although the white flowers are pale.)

Because of their other assets, English walnuts, figs and saucer magnolias are not often grown for their bark. Nonetheless, their pale gray bark shows off their stocky bare branch structure nicely, especially in front of an evergreen backdrop of redwoods or pines. The smooth metallic gray bark of European beech is much more subdued, but is what makes big old trees so distinguished.

A few deciduous trees and shrubs get more colorful as winter weather gets cooler. Instead of white or pale gray, their bark turns brighter yellow, orange or red. Some plants, like sticks-of-fire, do not need much cool weather to develop good color. Others get more colorful in colder climates, and contrast spectacularly to a snowy landscape. Locally, they should be well exposed to chill.

As the name suggests, the coral bark Japanese maple (‘Sango Kaku’) develops pinkish orange bark. It can get ruddier in colder climates, but may get yellowish here. Unlike other Japanese maples that get pruned to display their delicate foliage and branch structure, the coral bark Japanese maple sometimes gets pruned more aggressively to promote more colorful twiggy growth.

Osier dogwood is a shrubby dogwood that lacks colorful bloom, but compensates with ruddy brown, brownish orange or pale yellow bark in winter. (Dogwood bark . . . There is a pun there somewhere.) Because it lacks colorful bloom, it can be pruned aggressively after winter. Older canes that do not color as well can be pruned to the ground as they get replaced by new canes.

Posted on by tonytomeo · 15 Comments

Prune Now For Roses Later

70524thumb+The main problems with roses locally are not related to climate, soil, insects or disease. Warm and semi-arid climates of California happen to be some of the best places in the World for roses. Sure, many roses have problems with insects such as aphid, and diseases such as powdery mildew, but primarily because such pathogens proliferate among roses that are not pruned properly.

Yes, the main problems with roses are a direct result of improper pruning. Without adequate pruning, roses become overgrown thickets that shelter the pathogens that afflict them, but also lack the vigor to be resistant to damage. Like so many other domesticated plants, they were bred for maximum production of unnaturally big flowers, at the expense of natural resistance to pathogens.

Pruning eliminates superfluous growth and improves air circulation, which interferes with the proliferation of most types of pathogens. Most pathogens overwinter in fallen foliage that should get removed in the process. Pruning also concentrates growth of the next season into fewer new stems, which stimulates vigorous growth that hopefully grows faster than the pathogens that infest it.

Roses should be pruned while dormant in winter, after defoliation, and before buds start to swell at the end of winter. Hybrid tea, floribunda and grandiflora roses should be pruned back to only about three to six canes that grew from the base during the previous year. Older canes should be removed. Remaining canes should be only about two feet tall, and cut just above a healthy bud. Any growth below the graft union (where the basal canes originate) are genetically different suckers (from the understock or rootstock) that must be removed.

As growth resumes in spring, well pruned plants will produce fewer stems and blooms that are significantly more vigorous than those of inadequately pruned plants. Overgrown and inadequately pruned plants must spread their resources thin amongst more but significantly weaker stem growth that is much more likely to be damaged by pathogens. Aggressive pruning now pays off later.