Drought Tolerance Versus Container Gardening

Drought tolerant plants loathe root confinement.

There are probably just as many reasons to not grow plants in containers as there are reasons to justify container gardening. Some potted plants consume less water than they would in the ground, but only because their demand is proportionate to their limited size. They only want more water in the ground because they can grow larger.

The most drought tolerant of plants are actually the least practical for pots or even large containers. They tolerate drought because they efficiently disperse their roots so extensively. Since they can not adequately disperse their roots in pots, they rely on what they can get from a relatively limited volume of soil. However, even if watered generously, many drought tolerant plants simply can not produce enough finely textured roots to absorb enough moisture.

For example, eucalyptus trees want to begin dispersing their roots while very young. If confined, their long and wiry roots simply go around within their limited volume of soil, trying to find a way out. They can develop a few more fibrous roots than they typically would, but probably not enough to compensate for limited root dispersion.

Wild lilac (Ceanothus spp.), flannel bush, manzanita and smoke tree are not only sensitive to confinement, but have difficulty recovering from confinement if put into the ground after their roots have circled too much within a container. Pines and many other conifers are likewise sensitive to confinement, but some types can recover if the binding roots get severed before they go into the ground.

Plants with dense and fibrous roots are more adaptable to containers. Most succulents and common yucca are good choices. Ferns and some grasses also work nicely, but need to be watered rather regularly. Some types of arborvitae and juniper work better than larger coniferous evergreens. Some small bamboos can stay potted, but not larger types.

Annuals, compact perennials and many ground covers that provide color and fill in space around larger plants are naturally adaptable to container gardening, but their need for regular watering can not be denied. There simply is no practical way of combining container gardening and drought tolerance.

Real Deal

Oh My! I forgot about this recycled article from 2018. It most definitely conforms the Horridculture meme for Wednesdays.

tonytomeo's avatarTony Tomeo

P80203Stereotypes can be such a bother. For the past almost twenty years that I have been writing my gardening column, many of those who read the column have been making assumptions about who I am and how I behave. I actually find much of the behavior that I should conform to be rather objectionable. Even the lingo would be awkward for me. I am a horticulturist, and if you must know, an arborist as well. It is my profession. I did not take an interest in horticulture because I retired or got bored with my primary career. Nor did I flunk out at everything else. I am not a garden guru, flower floozy or hortisexual. I do not crowd my garden with garden fairies, repurposed junk or rare and unusual plants. There is nothing eclectic or quaint. There is no whimsy or magic, and most certainly NO riot of color!…

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Mexican Snowball

Mexican snowball is strikingly pallid blue.

The silly common name actually suits its plump rosettes of pale bluish succulent leaves. Mexican snowball, Echeveria elegans, forms small colonies that might resemble stashes of snowballs. Individual rosettes are circular, and a bit wider than tall. The widest are four inches or so across. The evergreen leaves are as neatly radial as scales of a pine cone.

Some may know Mexican snowball, and various other species of Echeveria and related Sempervivum, as hen and chicks. Big rosettes can produce so many small pups around their edges that they are reminiscent of mother hens surrounded by their huddled chicks. These pups are quite easy to separate for plugging into pots or elsewhere in the garden.

Mexican snowball is happiest in sunny situations with rather regular watering, but should tolerate a bit of shade and lapses of watering. For small trees in big pots, it can cover the surface of the potting media nicely. Pups plugged into crevices of stone walls might grow into clinging colonies. Tiny pink flowers with yellow tips bloom on wiry stems about now.

Succulents For Better Or Worse

There are all sorts of succulents.

Succulents, both old and new, have been something of a fad for quite a while now. There are certainly many reasons for them to be popular. They add bold form, texture and color to the garden. Most adapt excellently to container gardening. Many types are resistant to pathogens. Succulents are generally easy to maintain and equally as easy to propagate. 

However, one of the primary premises of the increased popularity of succulents is simply untrue. Contrary to popular belief, not all succulents are drought tolerant. Only those that are naturally endemic to desert or chaparral climates can survive with minimal irrigation. They neither expect nor require any more moisture than the rain that falls through winter.

Many succulents are naturally endemic to climates that are not arid. Some are even from tropical rain forests. Such succulents rely on watering to compensate for the local lack of rain through the long and warm summers. Furthermore, many succulents from chaparral and desert climates also want water if their undispersed roots are confined to containers. 

Many popular succulents are cacti. They lack foliage, and are instead armed with spines and thorns. (Spines are modified leaves. Thorns are modified stems.) Their fat succulent stems are green to compensate for their lack of foliage, by conducting all photosynthesis. Generally, most cacti actually are tolerant of drought, although less so within containers.

However, many of the most popular and trendy succulents have succulent leaves as well as succulent stems. Some obscure their stout stems within densely set foliage. Although some are chaparral plants that are somewhat drought tolerant, many require watering for adequate hydration. Even Epiphyllum, which are tropical cacti, require regular watering.

Furthermore, many of the succulents that can survive through dry summers without water take drastic measures to do. Various species of Aeonium and Echeveria let much of their older foliage shrivel to conserve moisture for the younger foliage. Echeveria retain much of their shabby dry foliage as insulation. So many of the succulents that have potential to survive without watering are happier with it.

Halston Junior

If gophers can procreate annually, the gophers who torment us now may be the great grandchildren of Halston Junior, and the great great grandchildren of Halston! However, Halston must be deceased by now, and Halston Junior is either also deceased, or is very elderly after three years.

tonytomeo's avatarTony Tomeo

P80610Apparently, the warnings were effective. https://tonytomeo.wordpress.com/2018/01/27/caution/ . They managed to avoid the traps and survive to perpetuate another generation under the lawn of Felton Covered Bridge Park. It is impossible to know if they are directly related to the now deceased Halston https://tonytomeo.wordpress.com/2018/04/21/halston/ who infested a landscape only about two miles away. It is unimportant. They all are intent on conquest.

Halston Junior, a baby gopher who may or may not be a descendant of the famed Halston, was found wet and shivering on the surface of the ridiculously perforated lawn. Rhody wanted to play, but was restrained from consorting with the enemy. The prisoner was detained, dried and put in one of Rhody’s blankets to recover. There was no formal interrogation, but the detainee was found to be well armed.

It is impossible to imagine what sort of damage such sharp and strong claws could inflict!P80610+

It is equally…

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Souvenir

This recycled article explains why I purchase almost nothing from nurseries.

tonytomeo's avatarTony Tomeo

P80609KNurseries are full of plants for sale. That is their business. They sell plants, and whatever plants need. With a bit of money, it is easy to purchase plants to compose an exquisite landscape. That is important to landscape professionals who make a business of composing landscapes to beautify the environments in which they work.

Those of us who enjoy home gardening might also purchase plants that we want for our garden. Yet, our home gardens are more than mere landscapes that are designed to simply beautify. The might also produce flowers for cutting, fruits and vegetables. Some might produce firewood. Gardens are usable spaces for active lifestyles. They are spaces for us to grow whatever we want to grow.

I buy almost nothing for my garden. The last item I purchased was a ‘John F. Kennedy’ rose, and I only did so because it was easier than growing one…

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Six on Saturday: Plebian

Refined gardens are interesting. They are pretty also. Many are impressively colorful. It is easy to understand why refined gardens are as popular as they are. However, they innately lack quite a bit. Furthermore, they demand more attention that what would naturally grow wild. We are very fortunate here, that the refined components of our landscapes are rather minimal, and must conform to the unrefined components of the surrounding forests. We occasionally add a few new plants, including annuals. Much of what grows here now was once refined, but has gone wild. They are the plebian of horticulture.

1. Zinnia were just recently planted for summer. They are some of the most refined flowers now. There are not many annual bedding plants here, and none live in big beds. These are in a row.

2. Alyssum were planted as summer annuals sometime in the past. These were likely planted about a year ago, and survived through winter. They would likely be white if they grew from seed.

3. Alstroemeria are too aggressively perennial. They were planted intentionally, but overwhelmed the mixed perennial bed they were in. We tried to remove them, but a few continue to bloom.

4. Geranium, or zonal geranium, which is just a rather mundane Pelargonium, was plugged as cuttings and left to go wild. It happens to be one of my favorites because I have always grown it.

5. Calla must have been planted intentionally somewhere and sometime in the distant past, but was dug up and dumped with what became fill dirt here. It now blooms on the side of the road.

6. Poppy, or more specifically, California poppy, which is the Official State flower of California, grows wild, of course. They are some of the least refined flowers now, but also, among the best!

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/

Oleander

Oleanders add color to the commute.

As long as freeways have been getting landscaped, oleanders have been contributing their profuse white, pink and red bloom. Heat, exposure and lack of moisture do not seem to bother them. They have become less common recently only because of new diseases that had never before been problematic. The diseases do not necessarily kill all oleanders everywhere, but are serious problems where the nurseries that grow most oleander are located.

The largest oleanders can get more than fifteen feet tall, and can be pruned up as small trees with multiple trunks. Oleander trees with single trunks almost never stand up straight, and do not want to give up their stakes. Because flower clusters develop at the ends of new growth, frequent exterior pruning or shearing inhibits bloom. Dwarf cultivars that are naturally proportionate to their space will bloom better than larger types that need to be pruned for confinement.

Oleander flowers are about an inch or two wide, with five petals, although some have ruffly ‘double’ flowers. Unfortunately, double flowers tend to hang on as they deteriorate after bloom. Some oleanders are slightly fragrant. The name ‘oleander’ is derived from the similarity of their leaves to those of olive trees (‘Olea‘), although oleander leaves can get three times as long.

Be Careful With Toxic Plants

Toxic plants can be quite appealing.

Plants are so much more intelligent than they get credit for. Many use color, fragrance and flavorful nectar to get insects and animals to disperse their pollen for them. Some provide fruit for animals that inadvertently take and disperse their seeds. Others use barbs or sticky substances to attach their seeds to unknowing animals that take them away. Plants have all sorts of techniques for exploiting those who are more animated than they are. After all, immobility has certain disadvantages.

Because plants can not get away from the animals and insects that eat them, many have developed techniques for being unappealing. Plants that live in deserts where edible foliage is relatively scarce are famous for their nasty thorns and spines, like those of cacti and agave. Hellebore and poinsettia have caustic sap that make them unpalatable. The naturally aromatic foliage of many edible herbs, like rosemary and lavender, is actually intended to repel grazing animals with sensitive noses.

Some plants unfortunately rely on toxicity for protection. Many plants are only partially toxic. For example, apples are intended to be eaten safely by animals that disperse the seeds within, but their seeds are toxic enough to avoid getting eaten by rodents after dispersal. Potato, tomato, rhubarb, asparagus and elderberry plants all produce edible fruits or vegetables, but also have poisonous parts. Some edible fruits and vegetables, like grapes and onions, are edible to humans, but toxic to dogs.

Foxglove, angels’ trumpet, morning glory, yew, rhododendron, azalea, oleander and castor bean are some of the more notably toxic plants often found in home gardens. Wisteria, holly and ivy produce toxic seeds and fruits. Dieffenbachia is a popular but very toxic houseplant. Although mostly safe, toxic plants can be a problem where young children might put things into their mouths, or where puppies are in that chewing phase.

O

Horridculture on Wednesdays used to be about aberrations of horticulture. I would contend that this recycled article could potentially conform to that tradition; but that is because I find disruptive wildlife to be objectionable. I suspect that most would disagree. It seems that everyone likes Kenny. https://tonytomeo.com/2018/09/16/kenny/

tonytomeo's avatarTony Tomeo

P80530

‘O’ is for ‘opossum’. That it the proper common name for the familiar North American critter who lives in or near many home gardens where fruit, vegetables or pet food are available. When a similar critter was found in Australia, it was given the same name by someone who did not spell it properly, hence ‘possum’. It is marsupial, and therefore related to many familiar Australian critters like koalas, kangaroos and the most terrifying of all, wallabies. Well, if the North American name can be applied to an Australian critter, it only makes sense that the Australian name can be applied to the North American critter. Thought technically and correctly ‘opossum’, many of us know them simply as ‘possum’, without the preceding ‘O’.

Opossums have a vast native range in North America. They can live anywhere that does not get too cold for them. They have likely always lived in…

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