Superbloom Highlights Local Mediterranean Climate

Rosemary can bloom longer with irrigation.

It does not happen often. The average frequency is about ten to fifteen years. However, it occurred in both 2017 and 2019, prior to this spring. That is enough for thirty to forty-five years! The current superbloom is only now finishing locally. It may continue through most of May near the coast farther North. The best bloomers enjoy the Mediterranean climate.

Climate is the typical and seasonal weather pattern of a region. The local Mediterranean climate is typically mild and somewhat arid. Almost all rain occurs between late autumn and early spring. Rain is otherwise rare. Winters are cool but not too cold. Summers are warm but not too hot. Native and some exotic flora knows how to exploit such climates.

Some exotic flora that prefers other climates also seemed to demonstrate a superbloom. Some merely responded to the unusually cool weather last winter. They appreciate more vernalization than they typically experience here. Some species enjoyed the unusually abundant rain last winter. Some species enjoyed both extra rain and extra vernalization.

Native species and exotic species from similar Mediterranean climates are a bit different. Their superbloom happens at the same time, and is also a response to earlier weather. However, it is also a response to later weather. They know that Mediterranean climates get warm and arid through summer. They are in a rush to finish blooming while they can.

Superbloom is how many species accomplish all their annual bloom within a brief time. They begin as soon as cool and stormy wintry weather finishes. They finish before warm and dry summer weather desiccates their flowers. Of course, such bloom may not be so spectacular after typical winters. It is only superbloom after exceptionally wintry winters.

Some species that exhibit superbloom in the wild bloom later for irrigated home gardens. This includes some exotic species from similar Mediterranean climates elsewhere. Such climates are present in small portions of Australia, South America and Africa. Obviously, most Mediterranean climates are around the Mediterranean Sea. Most exotic plants that are most adaptable here are from such climates.

Ornamental Grasses

Pampas grass was once appreciated for its appealing foliar texture and strikingly elegant bloom.

Lawns are among the most useful of landscape features, but are also the most horticulturally incorrect. They require such constant maintenance and so much water that they give grass a bad reputation. Yet, the turf grasses that are used for lawn are actually a minority among grasses. There are so many more grasses, including a few turf grasses, that can add color, texture and the seldom considered asset of ‘motion’ to the landscape.

Most grasses move nicely in a breeze. Old fashioned pampas grass, with remarkably limber and long leaves, is one of the best for motion. As if the elegant foliage were not enough, billowy white flowers on tall sturdy stalks nod gracefully in season. (However, pampas grass gets quite large, has potentially dangerous foliage that can cause nasty paper cuts, and in rural areas, can escape into the wild to become an invasive weed.) Red fountain grass does the same on a smaller scale that is more proportionate to suburban gardens.

Red fountain grass also provides striking brownish red foliage. Blue festuca and larger blue oat grass, although insensitive to a breeze, provide really excellent pale blue foliage. The most popular variety of miscanthus grass is variegated with white. Hair grass is a weird yellowish green that resembles that of a rubbery fishing lure.

Besides the odd color, hair grass also has an oddly soft texture that allows it to spill over the edges of retaining walls and pots, with delicate autumn flowers that hover above like a swarm of gnats. Mexican feather grass seems somewhat coarse up close, but has the uniform texture of wheat at a distance. Switchgrass has a more rigid texture, and stands more vertically than other softer grasses. Feather reed grass does both, with flowers that stand vertically above the soft billowy foliage below.

There are as many different kinds of grasses as there are variations of color, texture and motion. Only a few are annual. Almost all are perennial. There are a few in between; perennials that die out in a few years. Most grasses are only a few feet tall. Some never get taller than a foot. Yet, a few get several feet tall.

Most grasses are at their best if they get cut to the ground every few years or even annually. However, some need no maintenance except only for watering. If satisfied with watering, some grasses can sow their seed to cover the outskirts of a landscape, and can be an appealing alternative to ground cover. There are even a few grasses that will naturalize without watering.

Bloom Is Bountiful For Spring

Many flowers bloom only for spring.

Bloom that was delayed by the unusually wintry winter is making up for lost time. Spring bulbs, flowering cherries and deciduous magnolias were amazing. Wisterias and lilacs continue their pastel display within some climates. More flowers bloom during springtime than at any other time of year. Even roses of summer will begin their performance soon.

Pollination is the priority of all flowers. The majority of flowers exploit wind for pollination. Because they need not attract pollinators, they are neither very colorful nor very fragrant. Colorful and fragrant flowers are the minority that compete for the attention of pollinators. This includes the same colorful and fragrant flowers that are desirable for home gardens.

Whether reliant on wind or pollinators for pollination, flowers adhere to a strict schedule. Some colorful and fragrant flowers want to be receptive while their pollinators are active. However, pollinators are more likely to adjust their schedules to exploit favorite flowers. After all, there is another major incentive for spring bloom. Seed needs time to develop.

Pollination is the priority of all flowers because it is how they generate seed. Some seed develops fast enough to grow into new plants within the same year. Some annuals can actually procreate for a few fast generations annually. Most seed develop slower though. They mature during summer, overwinter, and ultimately grow during the following spring.

For now, garden enthusiasts should enjoy the most abundant bloom of the year. That will not require too much exertion. Fresh fruit of summer will develop later. Some flowers that deteriorate without producing fruit may justify deadheading. This redirects resources for vegetative growth, and eliminates any unwanted seed. Besides, it might be a bit neater.

The most profuse spring flowers generally bloom only once annually. They will not do so again until next spring. Some less profuse bloomers may repeat with later bloom phases through summer. Of course, some flowers bloom within other seasons between summer and even winter. Their individual schedules are appropriate to the climates that they are originally native to.

Shear Abuse

Cascading rosemary should actually cascade rather than get shorn into submission. (For this situation, it is subordinating to the climbing Boston ivy below.)

You can make fun of the decadent hair styles of the 1980s all you like; but you must admit that they were better than what came later. Back then, the assets of each particular type of hair were exploited instead of destroyed; sculpted instead of chopped into submission. Sadly, landscape maintenance evolved in a similar manner.

So many trees, shrubs and ground covers are either shorn too much to develop their naturally appealing forms, or not pruned severely enough to allow space for resulting new growth to mature and bloom like it should. Gardeners are notorious for shearing anything within reach. However, they are also notorious for allowing certain ground covers to get too deep and overgrown.

Trees that are short with multiple trunks when they first get planted are more likely than taller trees with single trunks to be shorn into nondescript shrubs. Olive, Japanese maple, tristania (laurina) and crape myrtle are commonly victims of this abuse. They are not only deprived of their form, but their grace and foliar appeal as well. Shorn crape myrtle may never be able to bloom.

Oleander, bottlebrush, arborvitae and various pittosporums that make nice informal screens in their natural forms are likewise very often shorn inappropriately and needlessly into all sorts of odd geometric shapes. Fortunately, pittosporums tend to make excellent formally shorn hedges as well as informal screens. Yet, when shorn without a plan, they more often develop into herds of noncontinuous geometric shapes. Oleander and bottlebrush, like crape myrtle, may never bloom if shorn too frequently.

Ground cover more often has the opposite problem. It does not get mown enough, or otherwise pruned down to stay shallow. This may not be a problem in most of the space covered by ground cover, but does make for hedge-like edges where the ground cover meets walkways, with all the problems of improperly shorn hedges. These edges can be softened if sloped inward and rounded off on top. However, lantana, star jasmine, acacia redolens and the ground cover forms of ceanothus do not bloom on these shorn edges unless the shearing procedure gets done at the right time to allow for enough new growth to mature in time for the blooming season.

There is certainly nothing wrong with properly planned and properly shorn formal hedges; but not everything needs to be shorn. Plants should be selected to be proportionate to their particular application without abusive shearing. Like the hair styles of the 1980s, the assets of each particular plant should be exploited instead of destroyed.

Shade Imposes Limitations On Gardening

Hosta is tolerant of moderate shade.

Home gardens are becoming shadier. Modern homes are taller to fit closer together. Modern fences are taller to compensate. Densely evergreen trees and large shrubbery compensate more. Taller homes and fences, and denser vegetation, shade more of their smaller modern parcels. Not much sunlight can reach the soil of modern home gardens.

Portions of a garden that are too shady for gardening are not necessarily useless. During warm weather, patios, sheds and workspaces are cooler with shade. Koi generally prefer shade to sun exposure most of the time. Compost piles and woodpiles need no sunlight. Such utilization of shady areas leaves more sunny areas available for actual gardening.

Deciduous trees that let warming sunlight through for winter are less practical nowadays. They do not always obscure undesirable scenery as trees in modern landscapes should. Warming winter sunlight is not so useful to energy efficient modern homes anyway. It is useful for gardening though. That is why smaller evergreen trees are now more practical.

Such trees or large shrubbery can do what they must without creating too much shade. If they get only high enough to hide nearby windows, they should not shade solar panels. Nor should they fill eavestroughs with debris. Perhaps more importantly, they allow more sunlight through than larger trees would. Lower vegetation appreciates what it can get.

Some plants tolerate more shade than others. Some of the most tolerant are understory species. They naturally live within the partial shade of larger plants. Many have big dark green leaves to maximize sunlight absorption. Fern are familiar shade tolerant plants, but have finely textured foliage. Coleus and hosta have exquisitely colorful variegation.

Because most plants enjoy sunlight, the selection of plants for shade is limited. Rhododendron and azalea have a reputation for tolerance of shade. However, too much shade inhibits their blooms. Camellia and hydrangea tolerate a bit more shade, with less inhibition. Cast iron plant is a famously shade tolerant foliar perennial. Kaffir lily tolerates almost as much shade, and blooms splendidly.

Some Weeds Were Not Always Weeds

Pampas grass was planted intentionally a long time ago, but then became a weed.

Weeds can be so very sneaky; getting into the weirdest places, and taking on all sorts of forms. They are mostly annuals or perennials that infest lawns and beds, but can be shrubs, vines and even big trees that grow among desirable plants, in untended areas, in cracks in pavement and even in roof gutters and on flat roofs. Many look appealing at first, but then later get out of control and displace the plants around them, or wreck whatever fence, pavement or building they encounter. Heck, I even suspect that it was a weed that stole my neighbor’s Pontiac!

While the soil is still damp from earlier rain, the most common annual weeds that are just developing are easiest to pull. They will put up more of a fight later, after they have dispersed roots, and the soil has gotten a bit more firm. Perennial weeds that were already established before winter will be considerably more stubborn, but not as stubborn as they will be as the soil dries later. Bermuda grass and crabgrass are always nasty.

The biggest, sneakiest and most stubborn weeds are ironically descendents of substantial perennials, shrubs and trees that were once actually planted in gardens. They are sneaky because they look as pretty as their parents when they first appear, in order to dissuade us from pulling them. The problems are that they are often too abundant, and very often get into spots where they will be problematic as they grow.

For example, Acacia dealbata and black locust are rather appealing trees while they are young, especially when they bloom. This is why they were originally planted in local gardens. It is tempting to allow self sown seedlings to grow instead of pulling them when they first appear. However, because they were not actually planted strategically where they can necessarily be accommodated, they grow in random situations, too near to pavement, fences or eaves, or in areas that are already landscaped. As they mature, they can damage these features or the plants around them.

Privet, pampas grass, castor bean and a variety of palms, acacias, ivies and several other plants that do a bit too well in local gardens have certain potential to become invasive or aggressive big weeds. Tree of Heaven, giant reed, the various brooms and the most invasive of acacias  have not been available in nurseries for many years because they are so problematic, but continue to be some of the most invasive and aggressive weeds in California.

Vernalization Enhances Bloom And Growth

Unusually wintry weather enhances some bloom.

Some gardens continue to recover from the exceptionally wintry weather of last winter. Frost damaged some plants, and killed a few. Wind damaged trees. Excessive rain caused erosion and saturation. This collectively unpleasant weather inhibited some from maintaining their gardens. Yet, some plants that require vernalization are performing splendidly.

It seems like an odd juxtaposition. Bloom of some plants is so unusually robust amongst remaining weather damage. Some bloom is noticeably late while most is precisely on schedule. It is not so odd to the plants who seem to behave so oddly though. Whether they appreciate vernalization or dislike frost, they respond to the weather.

Vernalization is merely attainment of sufficient chill to convince plants that it is winter. Many plants that are endemic to climates with cooler winters appreciate such reminders. It initiates their dormancy and resets their respective schedules. They know that subsequently warmer weather initiates their growing or seed germination season.

Plants that are endemic to climates with mild winters are less reliant on vernalization. Some of such plants are vulnerable to frost. Canna are tropical plants from mountainous regions that sometimes experience frost. They die back harmlessly if frosted, and remain dormant until safely warmer weather. They react to chill, but do not require it seasonally.

Spring bulbs, forsythia and flowering cherries have already bloomed atypically boldly. Later flowering cherries, as well as purple leaf plum, lilac and wisteria continue to do so. Peonies are likely to bloom better than typical a bit later. They are rare locally because of their reliance on typically unreliable vernalization.

Some cultivars of apple and pear are likewise unreliable within locally mild climates. Those that normally perform well here may perform better this year. After early warmth to initiate bloom, stone fruit bloom can succumb to late frost. Last winter though, frost was continuous enough to delay bloom until after the last frost. Extra vernalization may instead enhance production.

Arborists Are Horticulturists Of Trees

Arborists work with the big trees.

Landscapers and gardeners are only the two most familiar of horticultural professionals. There are also landscape designers, horticulturists, greenskeepers and various nurserymen, just to name a few. Each of the many distinct horticultural professionals works within a specific horticultural industry; like each of the many different types of physicians works within a specific medical industry, even though many might work together in the same hospital.

Arborists are the horticultural professionals, or even horticultural ‘physicians’, who work specifically with trees. In fact, they had historically been known as ‘tree surgeons’  because they perform what might be considered to be surgery on trees. After nurserymen grow trees in nurseries, and landscapers install trees in landscapes, arborists take over to care for the same trees like gardeners take care of landscapes below the trees.

Arboriculture, or the horticulture of trees practiced by arborists, is important because trees are so different from other plants in the landscape. Obviously, trees are larger than anything else. Structural problems or instability can have devastating consequences, not only to the affected trees, but also to anything around them that might be damaged by falling limbs or even entire trees. Some trees are large enough, or even have limbs that are large enough to crush an entire home.

Arborists who are certified by the International Society of Arboriculture, or ISA, have passed an examination of their arboricultural expertise, and maintain their certification by attendance to educational seminars, workshops and other relevant ISA approved events. Certified arborists are the most qualified to assess the health, stability and structural integrity of trees, and prescribe any necessary arboricultural procedures. Such matters should not be trusted to other horticultural professionals who specialize in other aspects of horticulture.

The website of the ISA at www.isaarbor.com is the best resource for finding certified arborists and the tree service businesses that they are affiliated with. Arborists can be found within particular regions by city or ZIP code, or directly by name. The website also features all sorts of information about trees that is useful to anyone who lives with them or wants to add more to the landscape.

Of course, there is more to gardening than trees. For those who missed reading about it already, it is nearly time for the most locally grown of horticultural events. Spring in Guadalupe Gardens will be April 28, from 10:00 a.m. to 3:30 p.m., in the Guadalupe River Park and Gardens between Taylor Street and Coleman Avenue in San Jose. More information can be found online at www.grpg.org or by telephoning 298 7657.

California Native Plants Grow Wild

Some natives are difficult to domesticate.

California native plants seem like they should be very appropriate for home gardens. In the wild, they require neither irrigation nor maintenance. They are quite satisfied with local climate and soil. Of course, gardening with natives is not so simple. Home gardens are very different from wild ecosystems.

Furthermore, wild ecosystems here are very different from wild ecosystems elsewhere. California is a very big place, with many different ecosystems. Some alpine species from the Sierra Nevada would be unhappy on the coast. Some coastal species from Del Norte County would be unhappy in the Mojave Desert. California native plants should be regionally appropriate.

Therefore, chaparral species are generally most appropriate for local chaparral climates. Many riparian species perform satisfactorily here as well, but expect more irrigation. However, appropriateness to a climate is not the same as appropriateness to a garden. Actually, many chaparral species are unappealing within home gardens. Some are difficult to domesticate.

A few species of California lilac are native here. Any of them are pleased to inhabit local home gardens. However, some grow quite large, and then die after only ten years or so. They may not last even that long with typical irrigation. Few respond favorably to pruning. They prefer to grow wild. Such big, awkward and temporary plants are undesirable within many compact and refined home gardens.

Combustibility might also be a concern for chaparral plants. Some chaparral ecosystems rely on fire for periodic renovation. In the wild, some such ecosystems may burn as frequently as every few decades. After burning, fuel begins to accumulate for the next fire. Even if not copious enough to be hazardous, such accumulation can be unkempt.

Only a few specialty nurseries provide wild California native plants. Most nurseries provide cultivars of such plants that are more adaptable to home gardens. ‘Carmel Creeper’ is a densely sprawling California lilac that gets only a few feet tall. It is commonly available. The original species can get more than fifteen feet tall, with open branch structure.

Spring in Guadalupe Gardens

(This information is now outdated.)

Spring in Guadalupe Gardens, a celebration of healthy living, gardening and the environment, will be here in little more than two weeks, on April 28! The 5 kilometer Fun Run that begins at 9:00 a.m., an hour before anything else, makes its way through the park and back to the main event, where there will be various health professionals to share information about healthy living, and for health screenings. Other exhibits will feature information about the environment and green technology, including presentations about solar energy and worm composting. Recyclable electronic waste can be dropped off free of charge. There will be all sorts of lectures, workshops, activities for children and even dancing and live bluegrass music.

But honestly, the main reason that most of us who read this column attend Spring in Guadalupe Gardens is all the gardening goodies! There will be an abundance of all kinds of plants from all kinds of specialty nurseries. Spring in Guadalupe Gardens has always been a great source of rare and unusual plants, as well as some of the more familiar plants, at reasonable prices.

Not only will there be plenty of plants to buy, but experts and some of the nurserymen who grew many of the plants will be available for advice on selection and cultivation. Representatives from the American Fuchsia Society, the John. E. Stowell Dahlia Society and the South Bay Heritage Rose Group will be there selling their plants, and sharing their expertise and information about membership. It is not too late in the season to select warm season vegetable plants, including heirloom varieties, from the extensive assortment that will be available.

Besides the shopping, Guadalupe River Park Conservancy and Greenwaste will be giving away one free bag of compost to each household. The San Jose Heritage Rose Garden, which is the most extensive public collection of old-world roses in the Western Hemisphere, will be in full bloom and open for tours.

Spring in Guadalupe Gardens will be from 10:00 a.m. to 3:30 p.m., in the Guadalupe River Park and Gardens between Taylor Street and Coleman Avenue in San Jose. There is no charge for admission or parking. More information can be found online at www.grpg.org or by telephoning 298 7657. Registration for the Fun Run, which begins an hour earlier at 9:00 a.m., can be arranged at www.grpg.org/FunRun.shtml.