String of Pearls

Weird but elegantly pendulous string of pearls likes to hang around. It cascades nicely from hanging pots or tall urns.

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.

Ivy Geranium

Ivy geranium cascades splendidly from planters.

Venice in Italy is an ideal situation in which to demonstrate the potential of ivy geranium, Pelargonium peltatum. Because garden space is so minimal, potted plants that cascade from balconies above the canals are quite popular. Ivy geranium cascades so splendidly that some eventually reach the tops of downstairs windows from their upstairs balconies.

Ivy geranium can sprawl over shrubbery to seemingly climb a few feet high. Otherwise, it is unlikely to stand much more than a foot and a half high on the ground without support. If cascading over the edge of a planter, upward growth may be only several inches high. In window boxes, it obstructs minimal sunlight. However, it may hang six feet downward!

Ivy geranium propagates somewhat easily by cuttings of the almost succulent stems, but not as easily as zonal geranium. Its lobed, rounded and quite fragile leaves are about an inch long and two inches wide. Sporadic but continual bloom becomes more profuse for late summer and autumn. Flowers might be white, pink, red, lavender, purplish or striped.

Montbretia

Bright orange montbretia is quite reliable and resilient, but can easily become a weed if not groomed of fading flowers.

Once they get into the garden, montbretia, Crocosmia X crocosmiiflora, may never leave. They sometimes survive the demolition of their original garden to emerge and bloom in the garden of a new home built on the same site. Bulbs (actually corms) multiply surprisingly efficiently to form large colonies that should eventually be divided if they get too crowded to bloom. Ungroomed plants sow seeds that may be invasive.

The one or two inch wide flowers are almost always bright orange, but can sometimes be reddish orange, yellow or pale yellow. The branched flower stems are two or three feet tall or a bit taller, and stand nicely above the grassy foliage. The narrow leaves are about half and inch to an inch wide.

Licorice Plant

Licorice plant can become vegetative mulch.

This is not the genuine licorice of confectionery. This more popular home garden licorice plant, Helichrysum petiolare, is more of an ornamental plant than a culinary herb. Its mild foliar aroma resembles that of genuine licorice, but is very faint. Without disruption of the foliage, the aroma is imperceptible. Since the foliage can be toxic, the flavor is irrelevant.

Licorice plant is popular for its appealingly silvery foliage. Some cultivars are variegated. ‘Limelight’ is strikingly pale silvery chartreuse. The small, rounded and evergreen leaves are distinctly tomentous (slightly fuzzy). The sprawling stems tend to disperse over older growth, and might get deeper than a foot and a half. Mature plants get wider than six feet.

Licorice plant is susceptible to extremes of temperatures. Within more severe climates, it appreciates a bit of partial shade during excessively warm and arid weather. Foliage can roast from harsh exposure. Where winters are cool, foliage appreciates shelter from frost. Roots are susceptible to rot with excessively frequent watering, or inadequate drainage.

Peach

Fresh tree ripe peaches are best.

Of all the stone fruit trees like apricot, plum and cherry, none need more aggressive and specialized pruning while dormant in winter than peach, Prunus persica. The distinctively fuzzy fruit is so big and heavy that the weight of too much fruit tears limbs down. Pruning not only limits fruit production, but improves structural integrity, fruit weight distribution, fruit quality, and tree health. Mature trees should be kept less than ten feet tall, but often get twice as tall with much of the fruit out of reach.

Sweet Flag

Sweet flag might enjoy wasteful watering.

If unpaved drainage ditches and collection ponds were more common locally, sweet flag, Acorus gramineus, might be also. It can provide a nicely neat border for such waterways, where the ground is too steep and damp for mowing. It can migrate into muddy situations and even into shallow water. Its dense network of fibrosus rhizomes helps to retain mud.

‘Variegatus’, with elegantly elongated and variegated leaves, is the most popular cultivar locally. It is rare in nurseries, but occasionally shared by friends and neighbors who grow it. Propagation by division is very easy. Single shoots or clumps of shoots grow if merely plugged into damp soil or mud. ‘Pusillus’ lacks variegation, and develops stouter leaves.

Sweet flag aggressively excludes other herbaceous vegetation, but does not migrate too rapidly. Plucking shoots and plugging them elsewhere accelerates migration. The dense foliage might get a foot deep. Individual leaves are very narrow, like grass. The mundane bloom is easy to ignore and is uncommon where the soil is not often saturated or muddy.

Tipu Tree

Sidewalks and curbs prefer tipu trees.

It may not get too tall, but with appropriate pruning, the tipu tree, Tipuana tipu, spreads a broad canopy high enough to be a good street tree. A mature tree is not much more than thirty feet tall and at least as broad. Roots are not too aggressive. A slight bit of mess is rarely but actually more likely to be a problem. The pale yellowish flowers that fall early in summer are followed by a few seeds. Not too long after the seeds stop falling, the deciduous foliage starts to fall. The soft green leaves are pinnately compound, with eleven to seventeen leaflets that are about an inch and a half long. Tipu tree is still uncommon, but really should be more popular than it is.

Duckweed

Duckweed can thoroughly obscure a pond.

Ducks somehow find water. They eventually visit most home garden ponds that they can fit into. Duckweed, Lemna minor, is likely to come with them. It adheres to waterfowl and other wildlife for that purpose. It proliferates very efficiently, and almost typically becomes a nuisance. Eventually, proliferation in a healthy pond should stabilize to a tolerable rate.

Individual duckweed plants are tiny. Their oval leaves are typically less than a quarter of an inch long. Each floating leaf extends its single root less than three quarters of an inch into the water below. Plants produce no more than four rooted leaves before dividing into a few smaller plants to repeat the process. Bloom and subsequent seed are uncommon.

As a floating aquatic plant, prolific duckweed might obscure koi and submergent aquatic plants within garden ponds. However, it also helps stabilize healthy aquatic ecosystems. In fact, it is useful for bioremediation of agricultural and industrial applications. It absorbs detrimental substances from water, while producing fodder and biomass for composting.

Canna

Canna excels at orange.

Although not directly toxic, canna has a unique reputation of lethality. Its spherical seeds are so hard that they were historically used as shot. Many victims are now pushing up daisies. Those who survived were pulling out cannas.

Old fashioned varieties that get up to six feet tall seem to be at least as popular as shorter modern varieties that get less than half as tall, probably because their bold foliage is as appealing as their colorful but awkwardly structured flowers. The big leaves can be cool green, rich reddish bronze or variegated. Red, orange, yellow, pink or rarely white flowers that bloom from summer to autumn are striking amongst the lush foliage, but are too perishable to be good cut flowers.

Stems that have finished blooming should be cut to the ground to promote more colorful new foliage and bloom. Mature colonies (of rhizomes) can be divided while dormant through winter if they get crowded enough to inhibit bloom every few years.

Canna bloom as well as foliage seem to be so tropical.

Foxglove

Foxglove is the source of digitalis.

It is no coincidence that its generic name seems more pharmaceutical than horticultural. After all, the cardiac medication digitalis is an extract of foxglove, Digitalis purpurea. The plant is unfortunately very toxic. Because it naturalizes in several regions, it can be more hazardous than standardized medications. It can migrate undetected into home gardens.

Otherwise, foxglove is a delightful warm season annual with a rustic or woodsy style. It is actually a biennial that generates basal foliar rosettes during its first season, and blooms during its second season. Although technically monocarpic (so should die after bloom), it can produce a few short pups to bloom later. Seedlings can appear in random situations.

Plants from nurseries grew during a previous season, so are ready to bloom immediately for early summer. Their seedlings may grow through later summer and autumn, so might bloom for the following summer. Floral stalks generally stand between three and six feet tall. The tubular and somewhat pendant flowers are mostly pinkish purple, pink or white. A few modern varieties bloom yellow or apricot.