Fire Is Part Of Nature

P81106Plants have very different priorities from those who enjoy growing them. The colors and fragrances of flowers that we find so appealing are really designed to guide pollinators. The appealingly aromatic foliage of scented geranium and other herbs is actually designed to repel hungry insects and animals. Many tasty fruits are designed for seed dispersion by animals who enjoy them too.

Pollination, dispersion of seed and self defense are all part of what plants do in nature. They must also know how to survive in their respective natural environments. Many plants survive cold arctic weather. Others survive arid deserts. Many native plants want a bit of water through winter, but know how to survive through long dry summers. Many or most natives know how to survive wildfires.

As unpleasant as it seems to us, wildfires are very natural here. Native plants lack the mobility to get out of the way, so use other techniques to survive. A few, such as the two specie of redwood, survive by not being very flammable. More know how to resprout from their roots after they burn. Even more simply regrow from new seedlings. Then there those that use fire to their advantage.

Monterey pine trees tend to accumulate combustible debris. They also produce more seed-containing cones as they age and deteriorate. When they burn, all the debris burns so hotly that most of the other competing vegetation gets incinerated. However, the dense cones of Monterey pine protect the seed within, only to open to disperse the seed afterward. It is a rather ingenious plan!

Ungroomed desert fan palms burn at least as hotly, but survive because the hefty trunks protect the buds within. Each technique works for the specie that use it, but is not safe for home gardens! This is why combustible vegetation needs to be managed around the home. The rules are different in urban areas than they are where wildfires are a concern, but they are important everywhere. Even the most combustible of native plants, as well as exotics, can be reasonably safe with proper pruning and maintenance.


Nomenclature Is More Than Botanical

90515thumbSimply put, ‘nomenclature’ is how things get named. It is not exactly like naming a child or a dog, or even a new small country in the South Pacific. There is a certain technique to it that is more like naming cars. Well, it ‘was’ like naming cars, a long time ago when cars had simple names rather than numbers and letters. Coincidentally, nomenclature of plants is getting to be just as confusing.

Plants and other biological organisms are assigned Latin names, which for plants, are also known as botanical names. These names are universal, for everyone, everywhere in the World. Almost all plants also have common names that are more or less regional. That is why what is known as Norway maple here is known as sycamore in England, but both are Acer platanoides everywhere.

The first part of a Latin name designates the ‘genus’, which is the more ‘general’ of the two parts of the name. (genus = general) For example, all true maples, including those that are known as sycamores in England, are within the same genus of ‘Acer‘. Genus names are like ‘Buick’, ‘Oldsmobile’ and ‘Pontiac’ for cars. They distinguish a general group, but are no more specific than that.

The second part of a Latin name designates the ‘species’ which is the more ‘specific’ of the two parts of the name (species = specific) For example, within the genus off Acer, the Norway maple is designated as Acer platanoides. Species names are like ‘Electra’, ‘Riviera’ and ‘Skylark’ for cars. They designate specific cars within the big general group that is collectively known as ‘Buick’.

There are of course more general and more specific classifications as well. Just as Buick, Olsmobile and Pontiac are within the group known as General Motors, the genus of Acer is within the family known as Sapindaceae along with Aesculus (horse chestnut) and Litchi (Lychee). ‘Schwedleri’ is a cultivar (cultivated variety) of Acer platanoides, just as some Buick Electra are ‘Limited’.

Incidentally, rules of proper nomenclature dictate that Latin names are italicized, and that the genus name is capitalized, while the species name is not.

Some Plants Should Stay Wild

P80804+Native plants should be the most sensible options for local landscapes and home gardens. It seems natural that they would be the most sustainable, since they survive in the wild without watering, soil amendment or fertilizer. Once established in landscapes, they should be satisfied with the moisture they get from annual rainfall. Plants that are not native are considerably more demanding.

However, even native plants are not perfect. Some of the same qualities that help them survive in the wild are not so desirable around the home. To make matters worse, adapting to unnatural landscapes and home gardens can be as difficult for native plants as it would be for many of the common exotic (non-native) plants to adapt to the natural climate and endemic soils without help.

Natives obviously do not need much water. They certainly do not get much in the wild. They are resistant to drought because they disperse their roots so efficiently. The problem with this technique is that it does not work while plants are confined to cans (nursery pots). Once planted, new plants might take a bit of time to disperse their roots enough to survive without supplemental watering.

This might not seem like much of a problem for those who do not mind watering new native plants while they get established. New native plants still use less water than established exotic plants. The difficulty is that too much water can rot roots before they disperse! So, new native plants need to be watered regularly, but also need to not be overwatered! Monitoring them can be a hassle.

It might seem that larger new plants would be more resilient than smaller plants would be, but it is quite the opposite. Smaller plants (such as #1 or 1 gallon) disperse roots more efficiently, so get established sooner than larger plants (such as 5 gallon). Roots contained within small volumes of media (potting soil) are damaged less when planted than roots in larger volumes are. Roots of native plants, although efficient at dispersion, are innately sensitive.P90309+++++

Naturalizing Within Constraint Of Cultivation

90508thumbPampas grass, blue gum eucalyptus, giant reed, broom and Acacia dealbata are some of the best examples of the worst naturalized exotic species. They were imported for a variety of reasons or by accident, and now proliferate aggressively in the wild. With few of the pathogens they contend with in their respective native homelands, they have unfair advantages over locally native flora.

Such naturalization is a serious problem for native fauna as well. Monarch butterflies that swarm to the bloom of blue gum eucalyptus are amazing to observe, but are being distracted from native flora that rely on them for pollination. Both native and exotic rodents proliferate unnaturally within the protection of thickets of naturalized English ivy, and consume too many seed from other plants.

Fortunately, there is a difference between naturalization and sustainability. Many exotic yuccas can survive quite nicely in chaparral regions without irrigation or other intervention, but are unable to disperse seed and truly naturalize without the particular species of moth that are their exclusive pollinators in their respective native homelands. Cultivars of pampas grass are ‘supposedly’ sterile.

Some plants that seem to naturalize do not proliferate or migrate enough to become aggressively invasive or truly naturalized. That is why daffodil can be planted on roadsides to bloom annually, and hopefully multiply somewhat, but does not spread far from where initially planted. In fact, it is unfortunately less likely to naturalize, and more likely to slowly diminish through several years here.

Many plants that proliferate within the cultivation of our home gardens and landscapes will not migrate far from where they they get regular watering. Even after fancier and more colorful varieties revert to their most basic feral forms, they are delightful weeds that are more often left to bloom wherever they appear. Those that appear where they are not wanted are easy enough to eradicate.

These include sweet alyssum, forget-me-not, four-o’-clock, campion, cosmos and nasturtium.

Spectacular Bloom Can Be Lethal

70510thumbAfter providing remarkably striking foliage for many years, the biggest and boldest agaves bolt with spectacularly tall floral stalks that support horizontal pads of flowers. These stalks can bloom for months, and stand for months after bloom is finished. Then things get ugly. The foliage around each bloom folds back, desiccates and dies. There is no nice way to describe it. Bloom is death.

Plants that bloom only once and then die are ‘monocarpic’. Agaves are not truly monocarpic, since they do not really die completely. They survive by producing pups (offshoots) as their original rosettes of foliage die. Some agaves start to produce pups years prior to bloom, just to be ready. Most terrestrial yuccas (that do not form trunks) go through the same process shortly after bloom.

Pups can be so prolific that they get crowded. Because the larger agaves are so big, they can conquer a significant area with just a few pups. With all their dangerously nasty foliar spines, extra pups are not at all easy to remove. Once removed, pups can be planted elsewhere as new plants, but they will grow up into even more agaves that will eventually bloom and make more pups!

Removal of the carcasses of bloomed yuccas without getting stabbed by the sharply tipped leaves is challenging. Removal of the carcasses of big agaves is hellish! Spines of old foliage never go dull. Pups hiding below the old foliage are just as dangerous. Tall blooms must be cut down like small trees. The debris can not be recycled in green waste, so must be disposed of like trash.

Furcraeas, which are related to agaves and yuccas, produce fewer pups, or may not produce any pups at all. Of course, a bloomed plant without pups will die completely. However, the huge conical blooms (that resemble Christmas trees) produce bulbils, which are tiny new plants that can be plugged back into the garden to grow into new plants! Regardless of all the work, furcraeas, as well as yuccas and agaves (within reason), are worth growing for their dramatic foliage and impressive bloom.

Citrus On The Sucker List

90501thumbA five pound kumquat is a problem! It means something went seriously wrong. Anyone who grew one would concur. They are huge, lumpy, and very insipid, with ridiculously thick pale yellow rind around a small handful of uselessly fibrous pulp. They are protected by dangerously sharp and rigid thorns that can get longer than three inches. Even their irregularly wavy foliage is unappealing.

In reality though, there is no such thing as a five pound kumquat. These huge but useless fruits, as well as the associated thorns and foliage, are those of ‘shaddock’, which is the most common ‘understock’ for almost all grafted dwarf citrus trees. It is what keeps such trees compact, so that they do not get as big as orchard trees. It was there all along, whether we were aware of it or not.

Most citrus trees are composed of two genetically different parts. The understock are the lower parts that develop roots that are unseen underground. The desirable upper parts that produce the familiar citrus fruits grow from ‘scions’ that are grafted onto the understock. Graft unions are just above grade, where the texture of the bark above is slightly different from that of the bark below.

‘Suckers’ are stems that grow from the understock below the graft unions. Because they are genetically identical to the understock rather than the scions, they produce the same fruit and exhibit the same physical characteristics as the understock would if it were growing wild. Suckers can overwhelm desirable scion growth, which is how kumquat trees can produce huge five pound fruits.

Other grafted trees and shrubs, particularly fruit trees, get suckers too. New suckers appear as new spring growth develops. They should be peeled off of the main trunks rather than pruned off. As brutal as this seems, it is more efficient than pruning. Soft young shoots should snap off quite readily. This technique removes more of the callus growth at the bases of the suckers, which could develop more suckers later. Big older suckers should be pruned off as closely and neatly as possible.

Vines Are Naturally Social Climbers

70906thumbIf more of us knew how vines compete in the wild, fewer of us would grow them in our home gardens. Understory plants that are satisfied with the sunlight that reaches them through a higher forest canopy are the most passive. Taller trees compete for sunnier exposure above. Vines are the most aggressive as they climb and overwhelm trees to get the best exposure on top of everything.

English and Algerian ivies happens to be among the more efficient of aggressive vines. While young, juvenile growth creeps along the ground searching for victims. Once it encounters something to climb, the stems develop aerial roots so that they can climb vertically. Once the climbing stems reach the top of the support, they develop shrubby adult growth that blooms and produces seed.

In home gardens, ivy is a popular and practical groundcover. However, if allowed to climb as a vine, it can root into walls and ruin paint. Even if the vines are removed, the unsightly aerial roots remain. The shrubby adult growth can overwhelm and even shade out and kill the trees or shrubbery that originally supported it. If it climbs onto a roof, it can accumulate debris and promote rot.

Creeping fig is even nastier. Its network of clinging vines grafts together as it grows, and then strangles the supportive trees as they continue to grow within the constrictive network of grafted stems. Yet, it and Boston ivy work nicely and harmlessly on concrete freeway sound-walls where their aggressive behavior is a major advantage, and their clinging aerial roots are not a problem.

Wisteria and red trumpet vine are considerably better behaved, but even they will crush lattice and anything else they wrap around. If they get into trees, they quickly grow out of reach. They may seem to be more appealing than the trees that they climb are, but can strangle and kill substantial limbs. Even without aerial roots, red trumpet vine clings with holdfast discs that damage paint.

Even though many vines are practical for home gardens, their personalities need to be considered. Star jasmine and honeysuckle can either grow as groundcover or as climbing vines. They can get big, but are not often destructive. Potato vine works nicely on fences, but gets aggressive in trees. Carolina jessamine, lilac vine and mandevilla are some of the more complaisant of vines.

Gophers Go For Spring Vegetation

90424thumbHibernation is a luxury enjoyed by different animals in different climates, where much colder weather inhibits activity through winter. Gophers take no such extended time off here. They merely work less diligently through the cooler and rainier times, and maybe get out of the way if the soil they live in gets too saturated. Their minimal damage had probably been easier to miss or ignore.

Now it is spring! The weather is warming. The soil is draining. All the roots and vegetation that gophers eat are growing. The gophers that were here and somewhat active all through winter are really making a scene now, as they clean mud from their homes and excavate new tunnels. Babies are growing up fast and leaving home, and excavating new homes of their own. What a mess!

Many of the primitive techniques that were used in the past to mitigate gopher problems are ineffective, impractical or even dangerous. Pouring gasoline into tunnels and waiting a few minutes to ignite the fumes can start fires anywhere such tunnels resurface, and possibly out of view! Bare razors dropped into tunnels are potentially dangerous to anyone who happens to dig them up later.

Traps take some work and experience to set properly, but are still the best way to deal with gophers. They do not involve poison that can be dug up and eaten by someone else, or eaten by a gopher who staggers from underground to get eaten by someone else. As long as dogs are not allowed to dig them up, traps are likely only be dangerous to gophers and those setting the traps.

Conventional traps are set in pairs, in each of both directions of a lateral tunnel that is found by excavating back from the tunnel under an active gopher volcano (pile of displaced soil). Once set, the tunnels must be back filled to eliminate air circulation into the tunnel, which would warn a target gopher of intrusion. A bit of weedy vegetation added before back fill might help attract a gopher.

Setting gopher traps is easier to read about than to do safely. It is best to learn how to do it from someone who is proficient at it..

Plant Problems Are Sometimes Exaggerated

04It is not easy for wild trees to adapt to a refined landscape. After a lifetime of adapting to their native environment and dispersing their roots to where the moisture is through the dry summers, they must adapt to all sorts of modifications such as excavation, irrigation and soil amendment. Newly installed plants grow into a new landscape while some mature trees succumb to disease and rot.

Oak root rot is such a common disease in California that there are only a few places where it is not found in the soil. It is not often a problem to new plants, but often becomes a problem to mature trees that suddenly get more water than they are naturally adapted to, particularly if roots have been violated, and the soil has been amended to retain more moisture. Change is not always good.

However, many of the same trees that are so susceptible to oak root rot if the environment around them changes can be remarkable adaptable as young trees. California sycamore happens to be a riparian tree that naturally grows near water. Although old trees may not adapt well to change, young trees planted in new landscapes will adapt to the water that is available as they mature.

California sycamore trees that are adapted to landscape or lawn irrigation are not likely to be bothered by oak root rot until they get old. Realistically though, any old sycamore is susceptible to oak root rot. The only difference is that those that get more water mature faster, so get old sooner. A California sycamore tree planted into a home garden may live only one century instead of two.

Verticillium wilt is another disease that can be found in most places throughout California. It is notorious for severely disfiguring and killing ash trees and many other plants. However, it needs moist soil in which to proliferate. Because lawns are irrigated so frequently and often excessively, ash trees in lawns are innately susceptible to verticillium wilt. In situations that are not irrigated so frequently, newly planted ash trees can mature into healthy shade trees.

Citrus And Avocado From Seed

71227Is it possible to grow citrus from seed? The quick and simple answer to that question is, “Yes.” After all, many cultivars of citrus were originally bred from other cultivars, and then grown from seed. But of course, this an overly simplified answer to an unrealistically simple question about a surprisingly complicated process. Perhaps a better question is “Should citrus be grown from seed?”.

Almost all citrus are grafted for a variety of reasons. Those that are not grafted are grown from cuttings only because they do not need whatever advantages understock (or rootstock) provides for their counterparts. Either way, they are all cloned by some form of vegetative propagation. This ensures that they are all genetically identical to their parents, without potential for genetic variation.

Citrus have been bred and developed so extensively that most types are very genetically variable. Those that are the most variable tend to produce fewer seeds, and might even be classified as seedless. Those with more seeds are probably more genetically stable. Nonetheless, it is impossible to predict if seed grown citrus will resemble their parents, or be something totally different.

Furthermore, citrus are cloned from ‘adult’ growth that is ready to bloom and develop fruit. Those grown from seed start out with vegetative ‘juvenile’ growth that will not bloom. Juvenile growth is typically more vigorous and thornier than adult growth, and possibly wickedly thorny! Some types of citrus outgrow their juvenile phase quite readily, while others may take several years to do so.

Avocado trees grown from seed exhibit some of the same difficulties. Although they lack thorns, they do grow very vigorously and very tall for quite a few years before they bloom. By the time they develop fruit, the fruit could be too high to reach, and quite different from the original.

Just because citrus and avocados can be grown from seed does not mean that they should be. However, different is not necessarily bad. Many seed grown avocado trees get pruned into