Summer’s here in Sonoma County California and the rains have stopped. This means it’s time to water. Since water is increasingly precious it’s important to use it to best effect. My pruning mentor Dennis Makishima enlivened in me the love of growing trees in containers and it was he who said, “Watering is an art”. Those words changed me forever, remaking what might have been a mindless routine into a conscious relational act bordering on spiritual. As I came to understand it watering is a complex, intriguing aspect of plant care.
Effective watering depends on a plant’s needs, soil composition, sun and wind exposure, and temperature. A recurring concern is how much water and how often. Over-watering is especially problematic since we generally don’t see the effects until it’s too late with no remedy short of re-potting. To avoid this dilemma we learn from bonsai artists to use soil mix that is virtually without organic matter consisting only of drainage material. Most bagged potting mixes have high levels of humus, compost, etc. which retain water in such varying and unknown quantities that accurate assessment of soil moisture is difficult. Using the high drainage formula allows excess water to drain immediately. While eliminating the fear of over-watering this mix also means we must guard against drying out. So a regular seasonal schedule of watering is required. To help gauge soil moisture an inexpensive hydrometer may be available at local hardware stores or nurseries. In the absence of a hydrometer, a quick check of water retention can be done by lifting the container (when possible) to judge weight. A light container likely means it’s time to water. A plant that has seriously dried out can be dunked in a bucket of water; holding the soil level below water will elicit bubbles as air spaces are filled with water. Remove the container and water runs out to proper level. Another aspect of humus-free mix is that fertilizing is up to us. Proper fertilizing is an art unto itself and too lengthy a discussion for the current effort. Stay tuned.
Hose-end hand watering is best with a gently showering nozzle. This implement avoids splash-out of soil while freshening foliage without damage.
Most considerations for watering containers are applicable to watering in-ground plants. While clearly we are not responsible for overall soil conditions in our garden (e.g. loamy, clayey, sandy) amending that soil is critical. Adding humus-y composted material is almost always a good idea. It adds nutrients, aerates, and paradoxically improves both drainage and water retention. Hand-watering (holding a hose in hand) is generally ineffective for getting water to the roots of all but the slightest of bedding plants. For trees and shrubs a simple inexpensive sprinkler does the job nicely, especially when combined with a calendar and a standard household timer. For most trees, it’s best to water infrequently and deeply: every 3 to 4 weeks; 45 minutes; shrubs 20-30 minutes. Native plants may require less water, but please remember that drought “tolerant” plants may actually do somewhat better with slightly more water. Careful experimentation is the key. Established trees and shrubs should be watered out to the drip line (foliage circumference) as this is where the feeder roots grow. Watering at the trunk is largely ineffective. Newly planted specimens should be watered so as to encourage roots to spread out.
Regarding drip irrigation, there are pros and cons with both containers and in-ground gardens. On the plus side, drip allows us to water without being present and it can be automated. It helps sustain life, especially with initial planting. On the other hand, while seemingly carefree drip irrigation requires regular attention. We must examine emitters for location and potential clogging due to soil and bugs. Tubing should be checked for leaks, disconnects and kinks. Also, dissemination of water is limited by emitters (narrow gravity-driven trajectory) and sprayers rarely get deep enough. In addition emitters are rated at gallons per hour and it’s unusual to see a system set for more than 15 to 20 minutes. This might be ok for bedding plants but has little effect on trees and shrubs. Just as we water the newly planted increasingly toward the drip line, drip emitters must be periodically moved outward to accommodate spreading roots.
For me the biggest drawback to drip is that it separates us from actually tending to and interacting with our plants in an essential way. Hand-watering, when done consciously, affords an opportunity to inspect our trees forinsects, disease and general well-being. We become familiar with a healthy look and are therefore more aware of changes that indicate stress or threat. Perhaps the most profound benefit is the intimacy it brings – a chance to say hello to each plant and to bask in the silence of its reply.
Here in west Sonoma County, California, 5 miles from the Pacific Ocean, March is the turning point of the seasons. In the Osmosis garden, winter work is nearly finished with the anticipation of spring’s soft explosion at hand. Though the weather varies, the seasons are consistent. Winter is marked by the loss of leaves on deciduous trees indicating the relative inactivity or dormancy of all plant material. Among the first signs of spring are the flowers of plum, which precede leaf growth.
Window of Opportunity
The window of opportunity for winter pruning is in this dormant period indicated by bare branches. Insect activity is also reduced at this time, lessening the chance for infestation. Winter work falls into two categories: Structural Reduction & Correction and Refinement of the winter silhouette (look).We learn from Japanese gardens that within the garden walls trees are kept at human scale, not towering above, as is their wont. Therefore, a consistent effort to contain trees and shrubs throughout the year is ramped up in winter as dormancy allows for more aggressive pruning.
One such situation in the Osmosis garden is the presence of a planted Monterey Cypress. Left on its own it would dominate and outgrow the limited space it is afforded. Yet for nearly 20 years we have managed to keep it at approximately 15’ with a fairly natural appearance. Normally this tree would not be a good candidate for a garden but, it was a gift and we have taken it on as an experiment to see what might be the possibilities and limitations of this native plant.
We have a large Mayten tree (broadleaf evergreen) anchoring one corner of our tea garden.This fast-growing tree is necessarily reduced and thinned each winter. We also have two Douglas Firs (another native) which are maintained in our bath garden as large shrubs (!) at about 8’.
Osmosis has a limited number of Japanese Maples with each being planted at a primary location (path or pond) in the garden. Ranging in size from diminutive (18” x 36”) to person-sized (6’ x 5’) these trees must look excellent all through the year. This means winter pruning is required not only to set up a beautiful spring/summer look but also to treat the eye in winter to the intricate delicacy of bare branches.
Along with the evergreens previously mentioned Osmosis has a number of Pines that get close attention.We have three Red Pines and three Black Pines.Two of the red pines are structurally pruned in winter to maintain proper scale.All the pines are groomed of excessive needles both as a matter of appearance and to help limit spring growth by reducing photosynthesis.
Support plants such as Grasses and Tamamono (mound-shaped shrubs) are also seen to in winter.Grasses are cut to the ground in anticipation of spring’s regeneration while the sheared shrubs may get a thorough opening up with hand pruners to allow light and air to reach inner branches that back budding may occur. Back budding is the breaking out of new leaves on bare wood. The vitality of inner wood helps ensure fullness at the time of spring shearing.
Thinning of Bamboo is begun in fall and may continue into winter.Third-year culms (canes) will be dying back and are thus removed along with weak or excessively crowding culms.
Transplanting is also scheduled for winter again because of dormancy. This year we flip-flopped Hellebores with Red Buckwheat plants that found themselves in each other’s microclimates.We also removed a large and languishing Rosemary from our entryway and replace it with a grouping of three small Hinoki trees and an array of Manzanitas.
Advent of Spring
With the advent of spring, the gardener sharpens tools, restocks sunscreen and cinches up her belt in preparation for the marathon to come.The surge of the plant world is both inspiring and
daunting.With so much growth at once, the garden pruner must establish priorities.Decisions are based upon the degree of unruliness and visual prominence.
Though Japanese Maples are amongst the most meaningful plants in the Osmosis garden their gently soft spring growth is so welcome and complacent that pruning may be set aside for more pressing matters.
When the time comes, Maples are both thinned and reduced for proper scale and a natural look.The one caveat is that when maples are in full sun or receive a lot of afternoon sun care should be taken to not open large holes in the canopy as inner leaves and bark can burn if suddenly exposed to strong heat/light.
Importance of Hedges and Shrubs
One of the possibly more pressing matters mentioned above is the 30’ Green Dragon Hedge separating the meditation garden from its entry gate.The importance of this hedge cannot be overstated as it provides the hide-and-reveal effect so integral to Japanese gardens allowing for a gradual revelation as guests follow the path.Once grown out wild, this element becomes more of a distraction than subtle influence so it’s imperative to keep it in bounds.
At Osmosis, we use manual hedge shears rather than gas or electric powered.The cleaner, sharper result is well worth the extra time and effort in a garden where aesthetics encourage a peaceful meditative state.
Along these lines, the individual sheared shrubs(we use variously Berberis, Euonymus, SpiraeaandGermander) are sometimes overlooked in deference to the dramatic appearance of pines and maples yet their function in the garden is paramount as a grounding element and counterpoint to the focal trees.These smaller shrubs (Tamamono) must be tended with consistent care especially with spring’s first burst.
Perhaps flowering trees such as Camellias, Rhododendrons, Ribes and Magnolia present questions as to when to prune them.In all these cases, as with Plum, the flowers appear before the leaves.This means that a well-maintained plant won’t need pruning (except grooming and deadheading) until after the new vegetative (leafy) growth occurs and extends.Observation leads to pruning guidelines.
Lastly, in our discussion of spring pruning is the Japanese Black Pine.Whiles there are many approaches to pine pruning, here at Osmosis we
remove the candle growth in spring followed byselective thinning in fall and winter. Candle is the term for the initial spring shoot growing on pines. Candle growth generally signal the strength and will power of the tree as it tries to attain its genetic height (60’).This size being beyond “human scale” in the garden, forces us to meet the tree’s will with skill and an aesthetic will of our own. As they extend, candles initially look like tubes; when they stop extending needle open out from the tubes.It is at this time they are removed in favor of their replacements, which develop over the summer in greater numbers and lesser length.
We who garden are fortunate to be so attentive to the seasons as this draws us closer to the unseen world. Make sure you leave time to visit our gardens during your next visit to Osmosis. We also offer Horticultural Garden Tours throughout Spring and Summer for a more in depth look at the underlying Zen themes built into the rock arrangements and pond layout, as well as information about the planting themes and plant materials.
The clouds, cold and late rains seem to do what they can to stanch the onset of spring yet plums begin blooming on Valentine’s day as usual and cherries to flower by April with a host of magnolias in between. Our California natives join the fray in the form of pink-flowering currant and blue ceanothus.We meet again the urge of the world to become itself and we gardeners see to our preparations:tools are sharpened, irrigation supplies are inventoried, fertilizers applied and the weeding begins!
Spring pruning of deciduous trees like dogwood and Japanese maple usually begins around April 15th once the new leaves have come out and hardened up, that is, acclimated to sunand weather.The goal of Japanese garden pruning is to maintain an appropriate size (human scale) while instilling a look of age.This look is often a stylized version of much older trees that have been subjected to their environment’s gifts and trials: rain, snow, wind, heat, and drought.While much control and refinement is done in winter, spring follow up pruning is critical to maintaining this vision.While managing size by cutting back ends is paramount, inner foliage is thinned showing the intricacies of branching and the interplay of light and shadow.
Sheared plants are a staple in a Japanese style garden and proper shearing is an art.Along with stone, they are a fundamental grounding element bringing stasis amidst change.While sometimes overlooked, low sheared plants, called tamamono (horizontal oval in shape) can be many.The hard-edged contour is an integral counterpoint to the more natural forms of other trees and shrubs.In Japan, azaleas largely fill this need.Here at Osmosis, for ecological reasons, we use replacements such as escallonia compacta,dwarf berberis and euonymus microphylla.Once new growth emerges they look shaggy, blurring the crisp edge so important to their function.Consequently, a round of shearing is necessary in spring addressing some individuals 2 or 3 times as needed.
Of all plants in our garden pines are the one group allowed to look somewhat unruly in spring.Their new shoots emerge from buds beginning in
February and elongate into a tubular shape known as candles.Though there are many approaches to pine pruning, at Osmosis we allow the candles to extend fully until needles unfold from them.At this time they are removed (cut or snapped off by hand).This technique controls size while the subsequent summer growth is used to develop foliage density and limited incremental extension.
The balance of plants such as nandina, pieris, flowering quince and juniper are pruned as their new growth arises.These complementary shrubs are pruned in a more general way to add context and a natural feel to the garden.
Spring work can be busy here at Osmosis as in most gardens but the softening weather and vibrant life bring joy to every day!
With the softening of the light and cooling of temperatures comes a time for an out-breath in the garden. Autumn at Osmosis brings a relaxing sigh after the hurried intensity of summer. In the calm expanse of golden light, we look back to what has been: the surprises, accomplishments, and challenges; and we look ahead to the opportunities that winter rains will offer.
Here at Osmosis Day Spa Sanctuary in Sonoma County, California, Spring was enlivened by deep and late rains. Trees especially came out with a robust vigor. This was an expectation gratefully rewarded. The surprise was that this vigor did not translate into increased health throughout a very hot summer. Many trees seemed inexplicably weaker as the season progressed. Autumn, therefore, brings welcome relief for the garden as well as the gardeners.
Bamboo’s Falling Leaves
Though plant growth has slowed, the rain of falling leaves keeps gardeners busy raking. Raking of the paths and grounds is expected but benches, lanterns, stones and the plants themselves must be kept as pristine as possible. It’s interesting to observe that broadleaf evergreen trees (such as bays), as well as conifers, are losing countless leaves at this time. Bamboo, an evergreen, is dropping leaves at a surprising rate. For good hygiene and appearance groves must be raked and mulched. Pines, redwoods, and hinokis all display an inner browning of foliage that may drop eventually with winter storms if not cleaned by garden staff.
Lack of Rain
Anticipation of winter may stir in us the realization of how long the garden has gone without rain. Lack of rain combined with extremely low atmospheric humidity makes this the driest time of the year for plants. It’s important that irrigation be regularly monitored for accurate operation and that container plants be watered assiduously sometimes being dunked in large tubs or troughs where possible. Again in anticipation of winter rains the garden is freshly mulched with nutrient rich amendment. When percolated in by rain a mulch of composted humus and manure not only enriches to plant growth but helps keep the soil alive with microbes, insects and all manner of healthful fungi.
Fall Pruning of Evergreens
Garden pruning in the fall hasn’t the pace of summer yet opportunities for care and improvement abound. In Japanese-inspired gardens like Osmosis, many trees are pruned for human scale. This reduction often stimulates a reaction growth which must be addressed. As this growth slows in summer water sprouts on plum, crabapple and persimmon, for example, can be removed or cut back. On Magnolia, heavy summer growth is also removed in preparation for early winter flowering. In addition, fruit tress such as pear, apple and apricot may be thinned and cut back. At Osmosis, we have a large naturalized apple tree growing along the bank of Salmon Creek which is pruned as an ornamental, not to interfere with a vigorous fruit production.
Evergreens are also pruned at this time. Pines are thinned, shaped and cleaned of old needles. The same can be done with various Chamaecyparis.
The thinning of bamboo groves not only improves appearance by removing dead, dying, and spindly culms but also can help (along with fertilizing) to increase the size of next year’s shoots for added drama. Similarly, drifts of Nandina may be thinned to display their vertical canes from which they get their common name “sacred bamboo”, though not a true bamboo.
Yes, in gardening there is the Zen moment of NOW, but we are also keeping an eye on what has been and what will be. Winter will bring an ideal opportunity for planting and transplanting. Autumn is the time to be looking ahead to the possibility of these, often dramatic, adjustments.
Learn More about pruning Nandina in the following video! Get ready to be inspired!
The garden in spring is a growing thing; never more apparent than following a rainy winter such as we’ve experienced here in West Sonoma County.
Pruning is the subject at hand. The question is often asked whether winter is the best season for pruning. It is one of them but a spring such as this should put paid to the question. From maples and pines to hedges and ground covers, the garden’s plants are burgeoning: encroaching on paths, nudging neighbors, blurring definitions, feeling themselves in such abundance that nature’s drive is palpable. It’s a celebration in the garden! An explosion of flowers and tender new foliage. Yet at the same time a garden without defined space soon reverts to the wildness of nature. So not only are we weeding at full tilt, but the ebullience of spring alerts us to the need for pruning.With its absence of leaves winter asks for pruning, but with its leafy eruption spring demands it.
One of the most interesting forms of new growth occurs on pine trees. The Japanese Black Pine, the rounded Mugo Pine and our native Shore Pine all have very prominent spring shoots standing straight up like fingers or “candles” as they are referred to by garden pruners.From the thousand-year old tradition of Japanese gardens to today scores of techniques have developed for embracing the pine tree’s growth habit in the interest of control and style.Control and style are the watchwords of Aesthetic Pruning.
Here at Osmosis, an Asian-inspired garden, our approach to these enthusiastic candles is to remove them entirely banking on their replacement shoots over the summer months for health and style.
Indeed, the single candle removed will be replaced by a multiplicity of shorter shoots more conducive to the size and shape of the garden’s requirements.
Maples are another genus of trees prominent in Asian gardens and we have several varieties here at Osmosis.Even with winter pruning these trees need a spring thinning.There are generally two flushes of growth: one in early spring (April-May) and another in late summer (July-August).Spring growth on maples is usually fine textured and thick while summer growth can be more coarse and rangy.
Two broad categories of maples are upright and mounding (umbrella-style).Upright maples are reduced and opened at the top to control size as well as let light and air into lower and inner branches.The middle of the tree is thinned to reveal graceful structure and to enhance the interplay of light and shadow.Lower branches are pruned for horizontal effect, creating layers or planes.Mounding maples are usually of the dissectum type with finely cut leaves.Their weeping habit allows for increase in size (especially height) much more gradually than upright trees.This makes control less important while thinning is emphasized to show structure.The beautifully arching branches can be obscured as they lay on top of each other sometimes creating a dense mound.Pruning is approached in two ways: the outer branches may be gently lifted and cut back to reveal those beneath while the inner branches are thinned (surprisingly enough!) by working beneath and inside the tree where possible.
The focus here has been on two focal point trees as they are, being the most noticeable, the first to be pruned.As the season progresses and time allows, the background and other supportingplants are groomed.So now, take heart, and answer the call of spring’s beckoning!