Why Hire An Arborist?

Arborists work with the big trees.

Like the many different kinds of physicians who work in a hospital, there are many different kinds of horticultural professionals who specialize in particular disciplines. Although too commonly considered to be ‘landscapers’, and even though many do not work directly with landscapes, there are nurserymen, gardeners, landscape architects, horticulturists and arborists, to name a few.

Arborists specialize in the horticulture of trees. Only a few decades ago, arborists were known as tree surgeons, since they perform surgery on trees. Of all the horticultural physicians that attend to concerns in the landscape, arborists and their associated technicians are the most qualified to properly maintain trees.

Expecting a gardener to maintain large mature trees is like expecting a pediatrician to perform major surgery. Even the most proficient and educated gardeners are too specialized with maintaining other plant material in the garden to also be specialized with arboriculture, or the horticulture of trees.

Arborists who are certified by the International Society of Arboriculture, or ISA, have successfully passed and examination of their arboricultural aptitude. Certification must be maintained by attendance to educational seminars, workshops and other relevant events approved by the ISA.

The website of the International Society of Arboriculture, or ISA, at www.isaarbor.com, is the best resource for finding certified arborists and the tree service establishments that they are affiliated with. Arborists can be found within particular regions by city or ZIP code, or identified directly by name or certification number.

The ‘Public Outreach’ category at the ISA website features links to www.TreesAreGood.org, and ‘Why hire an arborist?’, as well as a few other links for consumers. After all, the website exists not only for professionals, but also to help consumers find professionals and to make responsible decisions about their trees, from the time they get planted, throughout their lifetime, and until they get old and eventually need to be removed.

The www.TreesAreGood.org link has all sorts of information about trees and their maintenance. There are many and various articles about the benefits of trees, the value of trees, tree selection, planting new trees, proper pruning techniques, insects and diseases, tree hazards, why topping hurts trees, and even an article about palms. Incidentally, the Fun Facts link mentions that the tallest tree is the coastal redwood, the biggest tree is the giant redwood, and oldest tree is the bristlecone pine, all of which are native to California.

Trees are of course the most substantial components of a landscape. Some will be around for years. Some will be around for more than a century!

Male Delivery

Flowers of all fruit need pollination for fruit to develop. Most are self pollinating. Some require pollination from another variety. Some are dioecious, so female flowers need pollination from male flowers. A few, such as figs and muscadines, are even more complicated, but they are topics for another article. For now, I am concerned with my female kiwi vine, which is growing like a weed, but would have been unable to produce any fruit without a male pollinator. It was not a planned acquisition. I grew it from cuttings from a bit of vine scrap that someone brought to dump in the debris piles here. Because it grew so well, I requested some male vine scrap from the same person who provided the female vine scrap. Obviously, since he grows the female vine in his home garden, he also grows a male vine to provide pollen. I wanted the scrap while it was dormant through winter, because that is when I prefer to start hardwood cuttings. By the end of winter, I figured that it was too late to start cuttings, and that I would need to wait to try next winter. Then, just a few days ago, the person who provided the female vine scrap brought me a small piece of the male vine, which was already foliated and growing! This presents a challenge, since I lack access to a greenhouse with bottom heat and mist. I cut the stem into five cuttings. Three have single axillary buds that are still dormant. Two are vascularly active terminal cuttings, which are merely short shoots that grew from two axillary buds that are still attached. All but the smallest leaves were removed from the terminal cuttings. So far, they seem happy under a jar. Now, I can only watch and wait.

Pittosporum tobira ‘Variegata’

Pittosporum tobira ‘Variegata’ makes good hedges.

Almost all pittosporums appreciate sunlight and warmth. Pittosporum tobira ‘Variegata’ is no exception. However, it tolerates a bit of more partial shade than most. Furthermore, its grayish and creamy white variegation brightens shady situations. Its distinctively convex and glossy leaves are a bit flatter and broader where shaded. Shade inhibits bloom also.

Pittosporum tobira ‘Variegata’ is more popular as a foliar hedge anyway. Its small trusses of pale white flowers are neither prominent nor colorful. They can be delightfully fragrant in abundance, though. Stems are quite stout and can eventually grow more than six feet tall. They are resilient to frequent pruning and hedging, and can be cut back if necessary.

Pittosporum tobira ‘Variegata’ seems to lack a common name that is genuinely common. That is why its botanical name is most popular. Some know it as mock orange, but this is also a common name of Philadelphus. Some know it as Australian laurel, but it is neither a laurel nor from Australia. Regardless of name or origin, it is content with local climates. Once established, it is undemanding, and may need no watering.

Hedging Produces Foliar Green Fences

Proper hedging technique is not complicated.

Motorized hedge shears are the most overused home garden power tools. They are very useful for hedging evergreen shrubbery into hedges and privacy screens. However, they too often shear vegetation that requires different types of pruning. They are fast and easy but not appropriate for all pruning applications. Even hedging is a specialized technique.

Unfortunately, the rules of hedging are too often ignored. Hedges are utilitarian features. Many provide privacy. Many obscure unwanted scenery. Some divide large gardens into smaller and cozier spaces. Most continue to function as they should even without proper maintenance. Consequently, problems associated with maintenance may not be evident.

Unshorn informal hedges are mostly simpler to maintain, but only if they remain unshorn. Ideally, they use species or varieties that mature to a desirable size and form. Therefore, they should not become too large or Obtrusive. Only a few wayward stems need pruning. Of course, species or varieties that grow too large for such application will need hedging.

Shorn or formal hedges are more likely to develop problems. They need regular hedging to maintain their size and strict form. Yet, even with the most diligent maintenance, many become overgrown. Many gain depth from front to back, to become obtrusive. Many gain more height than they should. Most become distended up high while subdued down low.

This happens because pruning cuts can be slightly farther out than they were previously. They are a bit farther out higher up because that is where most growth is. Hedging within former cuts can renovate overgrowth, but damages hedge facades. Fortunately, damage should be temporary. Severely overgrown hedges might require severe pruning, though.

As mentioned, hedges are utilitarian. They should perform their primary purpose without encroachment into usable spaces. Their typically evergreen foliage is generally external. Their interiors are generally bare stems and empty space. Therefore, a hedge can be as effective whether two or four feet from front to back. Four feet is merely a waste of space.

Six on Saturday: Bearded Iris 2025

Too many iris are blooming now to document. Therefore, I limited my selection to a few bearded iris, which includes one that is not within the landscapes at work. Perhaps some of the other species can be featured next Saturday. With so much in bloom, it is difficult to be selective.

1. Of these Six, only this one does not inhabit the Iris Garden at work. It inhabits a small roadside planter in front of the totally awesome White Raven Coffee Shoppe in Felton. I believe that it is more caramel and charcoal colored than it appears to be in this picture.

2. Of these Six, only this one is likely identified. It conforms precisely to the descriptions of ‘Rosalie Figge’, including its habit of blooming sporadically throughout the year, with abundant bloom about now. Another participant of Six on Saturday identified it as such.

3. This relatively small pale yellow but nicely fragrant iris might be feral. It was found at a dumpsite for landscape debris, so could have grown from a deadheaded seed. It would likely be bigger and more colorful if it had grown from a discarded rhizome of a cultivar.

4. This big blue iris is as floppy as beagle ears, and is so heavy that its tall stems fall over if not staked. That is why its nearly horizontal stalk is obscured in its background behind it instead of visible below it. It is not actually as purplish as it seems to be in this picture.

5. Although more billowy and likely a bit bulkier, this garish iris needs no staking. Its tall and rather thin floral stems are sturdier than they seem to be. This happens to be one of my favorite bearded iris in this particular group. It was originally a gift from a neighbor.

6. Color is again deficient. This bearded iris is not as purplish as it seems to be here. It is actually a rich burgundy red. I remember the origins of all the other iris here but can not remember how this one was acquired. I do not remember ever seeing it before this year.

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/

Gopher Purge

Caustic sap deters gophers.

The common name may be derived from ‘gopher spurge’, since Euphorbia lathyris is within the family of plants known as ‘spurge’, and it is also purported to ‘purge’ the garden of gophers and moles. Like all related spurge, it has caustic opaque white sap that is very irritating to the skin and toxic if ingested. This offensive sap prevents anything from burrowing through the roots, but unfortunately does not prevent gophers and moles from going around. Therefore, a garden that is adequately protected may also be crowded by gopher purge.

Individual plants live for only two years, but produce enough seed to seem like perennials. Their mostly solitary stems can grow to nearly five feet tall with foliage that spreads up to a foot wide in the first year. Tiny yellow flowers that bloom in the second summer are not remarkable; and can set seed without getting much notice before the plant dies. Gopher purge can naturalize without becoming too invasive in regularly moist or somewhat shady parts of the garden. It prefers to be watered occasionally in drier and sunnier areas.

The foliage of gopher purge is strikingly symmetrical. Each pair of grayish or bluish green leaves is perpendicular to the pairs above and below it, in a four ranked pattern. Except for the newest upper leaves, each leaf pair is also arranged in a generally horizontal plane, perpendicular to the vertical stem. Gopher purge seems to have been assembled in the garden instead of grown there.

Spring in Guadalupe Gardens

Spring is in the air.

(This article is recycled from many years ago, so contains outdated information.)

Spring in Guadalupe Gardens on April 23 is the big local gardening event of the Santa Clara Valley! Not only will it be within Guadalupe Park, surrounded by the various Guadalupe Gardens, but Spring in Guadalupe Gardens gathers together an impressive variety of local gardening clubs and vendors. There will be workshops, lectures, trail walks and garden tours, as well as fun activities for children, music and entertainment.

The Heritage Rose Garden, which is the most extensive public collection in the United States of America, designed for the preservation of the ancestors of modern roses, will be in full bloom. The Historic Orchard is a tree museum of the many fruit and nut trees that inhabited the vast orchards that once filled the Santa Clara Valley; many of which can be productive in modern suburban gardens.

Representatives of many local gardening clubs will be at Spring in Guadalupe Gardens, with information about their respective expertise, as well as membership. The John E. Stowell Dahlia Society, the American Fuchsia Society and the Master Gardeners of Santa Clara County will all be there, to name a few. I will be at the Gardening Advice Booth throughout the event, to discuss any gardening issues and questions.

When I can get away from the Gardening Advice Booth, I like to see what I can purchase from the many vendors. There will be more than forty. Most of my fuchsias, and some of my aloes and cacti were obtained at Spring in Guadalupe Gardens. It is common to find many uncommon tomato plants and roses.  There will also be garden art and paraphernalia. The Master Composters of Santa Clara County will be giving away free compost. One never knows what to expect at Spring in Guadalupe Gardens.

Earth Care Recycling will again host a free electronic waste drop off at the Visitor and Education Center, to collect all sorts of computer components, televisions, stereos, fax machines and telephones. Proceeds benefit the Guadalupe River Park Conservancy.

Spring in Guadalupe Gardens will be from 10:00 a.m. to 3:00 p.m. this April 23, just north of the Guadalupe Gardens Visitor and Education Center, which is located at 438 Coleman Avenue in San Jose.  Admission and parking are free. Just follow the signs from Coleman Avenue or East Taylor Street. More information about Spring in Guadalupe Gardens can be found at www.grpg.org or by telephoning 298 7657.

White on Wednesday

Syringa vulgaris ‘Madame LeMoine’ French hybrid lilac bloomed bright white and right on time as March became April, and is not finished yet. It was somewhat of a surprise, since it remains canned until development of the landscape that it should eventually inhabit. It does not grow much while canned, so was not expected to be so spectacular in bloom. It is so spectacular that it was temporarily placed into a prominent position within another landscape, with its can mostly obscured by other vegetation, until it finishes bloom.

However, regardless of how spectacular it is, it reminds me that white is not necessarily the best color for all flowers. White happens to be my favorite color, and lilac happens to be among my favorite early spring flowers, but to me, lilac bloom should be lilac colored. I mean, it really should be that lavender or pastel purple color of traditional and formerly common old fashioned lilacs. The only advantage to this white floral color is that it would be appropriate to situations in which white is the most desirable color, or where lavender is undesirable.

Just as many flowers are at their best in white, some are best with other colors. Southern magnolia, lily of the valley, moonflower, gardenia, Easter lily and old fashioned calla are exclusively white, and would look weird in any other color. Gladiolus, tulip, hyacinth and rose can be all sorts of colors, but happen to excel at white. A few other flowers that can be all sorts of colors happen to not excel at white, such as bougainvillea, crape myrtle, English primrose, tropical hibiscus, wisteria and, of course, lilac. Both white crape myrtle and white bougainvillea happen to have been selected specifically for landscapes here, so perhaps white lilac is not so out of place.

Californian Blue-Eyed Grass

Blue-eyed grass is not grass.

It is not a grass, and lacks eyes, but it is native to most of California and western Oregon. Blue-eyed grass, Sisyrinchium bellum, is related to iris, which actually sounds ocular. Its tiny flowers are typically rather purplish, but can be clear sky blue, or rarely white. Bloom continues through spring until summer dormancy. All foliage then dies back until autumn.

Blue-eyed grass develops small foliar tufts that expand quite slowly. It propagates easily from division of its thin rhizomes as it resumes growth in autumn. Plugging newly divided rhizomes adjacent to original foliar tufts accelerates expansion. Blue-eyed grass can self sow, but typically does so only sparsely. Its grassy foliage is typically less than a foot tall.

Although native and impressively resilient, blue-eyed grass appreciates a bit of moisture. However, it may never require irrigation, since it is dormant through the summer season. Irrigation might maintain foliage through much of summer, but if excessive, can cause rot. Blue-eyed grass prefers sunny and warm exposure, without contention from other plants.