There really is no way to neatly classify succulents. Many are spiny cacti with fleshy stems without recognizable foliage. Others are euphorbs (related to poinsettias) that may resemble cacti, or may instead have fragile leaves on fleshy stems. Aloes and agaves have bold rosettes of fleshy leaves that obscure their wide basal stems.
The most familiar succulents are small docile perennials, like the many varieties of jade plants and iceplants. Some are flowering perennials like begonias. A few are even grown as annuals, like busy Lizzie (impatiens).
So what do succulents have in common? Well, that is a good question that is open to interpretation. Most would agree that succulents have some sort of fleshy succulent parts for storing water through dry weather. These succulent parts are most often leaves or stems. Yet, yuccas, dracaenas and ponytail palm that are no more succulent than palms, are considered by many to be succulents like related aloes and agaves.
Many succulents are remarkably easy to propagate vegetatively (without seed). Most aloes, some agaves and many yuccas produce pups, which are basal shoots that can be separated as new plants. Agaves that do not produce pups while young will likely produce many pups after they bloom and begin to deteriorate. (Individual rosettes die after blooming.)
Despite the nasty spines that make them difficult to handle, cactus that produce multiple trunks can likewise be divided. Cactus can alternatively be propagated as large cuttings; but because they are so fleshy, should be left out for their cut ends to dry and ‘cauterize’ somewhat before rooting. Many euphorbs behave much like cacti, but are even more hazardous to handle because of their very caustic sap.
The majority of small succulents, like the many jade plants and iceplants, are notoriously easy to propagate by cuttings.
It is difficult to see how string of pearls, Senecio rowleyanus, is related to much more colorful daisies and asters. The small, fuzzy and sickly white flowers are not much to look at, and only clutter the elegantly pendulous and oddly succulent foliage. The round leaves are light bluish green, so actually resemble peas more than they resemble pearls. The stems are so very thin and limber that they can only stand a few inches high, but can cascade to three feet!
Although evergreen, stems of outdoor plants can be cut back while dormant through winter to promote fresher growth in spring. The pruning scraps are very easy to propagate as cuttings. Roots are undemanding and sensitive to rot, so should be allowed to get nearly dry between watering. Bright ambient light without too much direct sun exposure is best. Incidentally, all parts of Senecio rowleyanus are toxic.
Several species of Agave inhabit the landscapes here. Only a few are identified. Some of those that are unidentified could likely be identified if their identities were important to us. For some, identification would be as simple as researching our records. I know what Agave attenuata is only because there is nothing else like it. #3 is likely a variegated and dwarf cultivar of Agave americana. #6 is the surprise of these Six. It is a familiar species that was formerly identified as another genus. Although its relation to the Family should be obvious in regard to physiology, it is not visually similar to others of the Agave genus. I still know it by its older and perhaps less accurate designation. It works for me.
1. Pups of an unidentified agave that was removed last year are a concern because others just like this continue to develop where the agave was relocated from a few years earlier!
2. The parent agave got removed and dumped next to a greenwaste pile after gophers ate its base, but somehow survived. It fell over only recently. Maybe other gophers found it.
3. Gophers also ate the base of this other unidentified agave, which, like the other agave, seems to have survived somehow. Fortunately, it did not leave undesirable pups behind.
4. Agave attenuata arrived as a big cutting with a long stem, and by odd circumstances. The severed stem generated a big secondary rosette, which is now generating four pups.
5. The pup to the lower right of this unidentified agave indicates that its primary rosette may be about bolt and bloom. Although most agaves are monocarpic, their pups survive.
6. Surprise! Fresh from 1985, tuberose, which was formerly Polianthes tuberosa, is now Agave amica. We just installed three, with two more still canned. I hope for many pups.
Like so many fads often do, the vertical gardening fad has become trendier than it really should be. It certainly has practical applications, and is very appealing in the right situations. However, in the wrong situations, it can be more problematic than it is worth.
Vertical gardens can shade and insulate exposed walls, but really do little more than strategically placed shade trees, large shrubbery or even trellised vines can do in that regard. The disadvantage of vertical gardening is that it can hold moisture against the affected walls, and can promote rot if the planters are not installed properly. Planters over windows or decks drip just like any other planters do, staining or dirtying whatever is below. Only free standing vertical gardens (that are not attached to a wall) or those on concrete walls that are not susceptible to rot will not cause such problems.
Water borne pathogens (diseases that disperse in water) can proliferate more in vertical gardens because they get carried with the natural flow of water from top to bottom. Wherever any such disease gets established on a vertical garden, it will likely get carried to everything below. In the ground, such diseases spread slower since they only travel as far as water flows or gets splashed.
The obvious advantage to vertical gardening is that it makes it possible to grow many more plants in very limited space, which is excellent if there is no open ground for vegetable gardening. It can also be a great way to display plants like orchids and certain bromeliads that are more appealing if they hang from above. Staghorn ferns cling to walls naturally.
Another advantage is that vertical gardening can be so aesthetically appealing and unique. Vertical gardens of small, densely foliated succulents hung like tapestries to adorn exterior walls are so much more interesting than simple vines or shrubbery used to obscure such walls. Northern exposures that are too dark for most plants can be adorned with ferns.
Some but not all of of the many succulent plants known as ‘hen and chicks’ are varieties of Echeveria. Likewise, some but certainly not all Echeveria are known as ‘hen and chicks’. Echeveria are so variable that many do not seem to be related, although all have dense rosettes of succulent leaves. Some have very narrow leaves like miniature yuccas. Others have warty broad leaves. Foliage can be simple green, yellowish, bluish, gray, bronze, bronzy purple or variegated. The edges and tips of leaves of many varieties are blushed with red or purple that is more colorful in winter, or with complete sun exposure. Most Echeveria will tolerate light shade. Propagation is very easy from division of pups, stem cuttings and even leaf cuttings.
Cacti have thick, fleshy stems outfitted with nasty spines instead of leaves. Agaves and related aloes have stout, fibrous stems that are mostly obscured by thick, fleshy leaves. (Only a few somewhat rare aloes develop bare trunks and stems.) What they have in common is that they all are succulent plants, collectively known as succulents.
There are all sorts of other succulents. Humongous saguaro cactus have hefty trunks and limbs. Diminutive impatiens (like busy Lizzie) are grown as annuals for their colorful and very abundant flowers. Many succulents have succulent stems. Many have succulent leaves. Some, like the common jade plant, have both succulent leaves and stems. Trailing ice plants, leafy begonias, and sculptural euphorbs (related to poinsettias) are all succulents.
Many succulents store water in their succulent parts because they live in dry climates. Because moisture is such a commodity where they live, cacti protect their succulent stems with sharp spines. Agave protect their leaves with sharp teeth. Euphorbs are equipped with caustic sap, and many also have spines like cactus have. Fortunately, most succulents are not so unfriendly.
Almost all succulents are remarkably easy to propagate from cuttings or by division. In the wild, pieces of prickly pear cactus that fall onto the ground will begin to develop roots through the rainy weather of autumn and winter, and be ready to grow into new plants by spring. In the home garden, cactus cuttings should be left out for a week or more so that the cut ends will ‘cauterize’ (Actually, they just dry out a bit.) and be less susceptible to rot once they get plugged into the ground or pots to grow roots. Alternatively, clumping cactus that develop multiple main stems from the base can be divided, although the spines make handling them difficult.
Most aloes and some agaves produce basal shoots known as pups, that can be split from the main plants to grow into new separate plants. Agaves that do not produce pups while young typically start to produce pups after a few (or many) years, as they mature enough to bloom. Many of the larger types produce an abundance of pups after bloom, since the main shoot dies as flowers deteriorate. If desired, one or more of the pups can be left in place or planted back to replace the parent plant.
Most other succulents are even easier to propagate. Small cuttings can be plugged wherever new plants are desired. Some can even be grown from leaf cuttings!
Back when big spider plants or Boston ferns suspended in fancy beaded macrame were all the rage through the 1970’s, burrow’s tail, Sedum morganianum, was an unusual but also trendy succulent perennial for sunny spots in the home or sheltered and slightly shaded spots in the garden. The refined foliar texture and light bluish green color contrasted nicely with the big and deep green leaves of comparably trendy philodendrons. The thin stems are too limber to stand up, but cascade excellently. Plants in the garden that get pruned back while dormant in winter can easily get two feet long through summer. Without pruning, big plants can get longer than six feet. Pruning scraps and even the small but plump leaves can be rooted and grown into new plants. It is impossible to prune or even move burro’s tail without dislodging some of the leaves anyway. Watering should be regular but not excessive, but then minimal for plants in the garden through winter.
With only one exception (#6), everything that I added to my downtown planter box was recycled from somewhere else. Almost all of that which I added came from the garden of the mother of a now deceased old friend, so has major history with me. The original cuttings rode around for more than a month on the dashboard of the old station wagon prior to getting plugged. Yet, I do not know many of their names. Only #5 inhabited the planter box before I got there. Nowadays, bits and pieces generated from occasional grooming of the planter box get recycled elsewhere. Many are shared with neighbors.
1. Tree houseleek grew almost as big as small tumbleweeds. Except for two Indian hawthorn trees that were installed when the planter boxes were built, they are the most prominent features.
2. Unknown succulent resembles tree houseleek, but stays much lower. A neighbor requested ‘Australia’ canna (#6) because this and tree houseleek produce so much pallid light green foliage.
3. Unknown Aloe is more appealing in the planter box than these shriveled cuttings are. I think that it might be more appealing if it bloomed. After a few years, I have not seen a single flower.
4. Unknown bearded is not a good choice for a planter box downtown. It blooms only once annually, and the few flowers get picked. They are slightly grayish white, so are not even very pretty.
5. Variegated lily turf is one of the few plants that was already in the planter box when I go to it. Some of it reverted to unvariegated, and became even more invasive, and then more abundant.
6. ‘Australia’ canna is the only item that I actually purchased for the planter box. I got it because a neighboring merchant expressed an appreciation for bronzed foliage. It does not disappoint!
This is the link for Six on Saturday, for anyone else who would like to participate:
Until the patent expires, unauthorized vegetative propagation (cloning) of ‘Angelina’ stonecrop, Sedum rupestre ‘Angelina’, is still illegal. However, it regularly flaunts its own unlawful proliferation wherever dislodged bits of stem can find anything to take root into. It can be just as happy to root into cracked concrete as in bare soil. Yet, it is a surprisingly complaisant small scale ground cover that cascades only several inches over stones, low retaining walls or the edges of planters.
Without getting more than four inches deep, stems root as they creep indefinitely but slowly along the ground. The bright yellowish evergreen foliage and bright yellow flowers that bloom about now contrast nicely with darker green or bronze foliage. Exposed foliage can get blushed with orange in winter. Shabby plants regenerate vigorously after getting pruned back. Pruning scraps sprinkled over bare soil and lightly mulched with finely textured compost will happily but illegally grow into more of the same. ‘Angelina’ stonecrop likes somewhat regular watering, but can survive with less.
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.