Perennial Plants Keep On Giving

Can a canna be too perennial?

Many popular annual bedding plants have potential to be perennial if they get a chance. Cyclamen commonly perform as a cool season annual, only until replacement with warm season annuals. However, after summer dormancy, their tubers can generate foliage and bloom again for several following winters. Replacement is just easier than maintenance.

Real annuals complete their entire life cycles, from germination to dispersal of seed and finally death, within a single year. Biennials generate vegetative growth through their first year, and then disperse seed and die during their second year. Perennials perform for at least two years, whether or not they get any opportunities to do so within home gardens.

Home garden culture complicates this classification though. Those who enjoy gardening expect perennial plants to reliably perform for many years or indefinitely. Many perennial plants do so with only minimal intervention. Some are self-sustaining, and might seem to naturalize. That may be why so many smaller or less vigorous types classify as annuals.

Another qualification of perennial plants is that they lack woody stems and roots. In other words, they are herbaceous. Palms and species of Yucca that develop trunks classify as perennial plants also, but for simplicity, the larger types are herbaceous trees. Generally, perennials are terrestrial. A few are epiphytic (live in trees) or lithophytic (live on stones).

Although several perennial plants can survive indefinitely here without intervention, most perform better with some degree of attention. Most ferns are neater if groomed to remove deteriorated fronds. Many grasses benefit from severe shearing during winter. African iris blooms better in response to regular deadheading to remove developing seed capsules.

Perennial plants are very diverse. It is impossible to generalize about their maintenance. One commonality among many is that they multiply. Lily of the Nile can produce so many individual shoots that it can eventually become too congested to bloom. Division of such shoots every several years or so promotes bloom, as well as propagates more plants for elsewhere in the landscape.

Daylily

These flashy blooms are remarkably easy.

As the name implies, each individual flower of daylily, Hemerocallis, lasts only about a day. They open just after dawn, and wither by dusk. However, bloom last from a week to a month because there are several flowers on several stalks. These flowers take turns blooming, so that a flower that blooms today will likely be replaced by a new flower tomorrow, until bloom finishes. Some daylilies bloom early in spring. Others wait until summer. A few bloom again, as late as early autumn.

Flowers can be almost any color except for blue or white, and typically have a a different color in the throat. The most popular varieties are bright yellow, pastel yellow, orange, pink or rusty red. Purple flowers are not quite as flashy as the color implies. Each flower has six petals, (which are actually three petals and three sepals). Bare stems hold the flowers about two feet high, well above the clumping grassy foliage. Some stay only a foot tall. A few get considerably taller. Plants should be groomed of finished flower stems, and may sometimes want to be groomed of deteriorating foliage. Daylilies known as ‘deciduous’ daylilies shed all foliage by autumn.

Perennials provide foliage and bloom

Bloom can repeat in season perennially.

Does anyone really know what a ‘perennial’ plant is? It is obvious that it is not an ‘annual’ plant that lives only a single year. A ‘biennial’ plant produces vegetative (non-blooming) growth in the first year, and then blooms, develops seed, and dies in the second year. A plant only needs to live more than two years to be a perennial plant, or simply a ‘perennial’. Well, that does not narrow the definition down much. Bristlecone pine can live for thousands of years, but is not often thought of as a perennial.

In simple home gardening terminology, a perennial not only lives for more than two years, but does so without producing significant woody stems. Yes, this also happens to include palms and trunk forming yuccas (which are known as ‘perennial trees’), but that is another topic. Some perennials live only a few years. Some can live indefinitely by replacing their stolons, rhizomes, bulbs, tubers or whatever they regenerate from as their old growth gets left behind.

For example, bearded iris spread by fleshy stems known as ‘rhizomes’. As they grow from the forward tips, the older ends that get left behind will rot away. They are constantly replacing themselves, without leaving evidence of how long they have been doing so. (In other words, it is impossible to cut one down to count the rings.)

Many plants that are known as annuals are actually perennials, but get removed and replaced during their respective dormant season. Busy Lizzy can regenerate each spring if their roots do not succumb to frost in winter. Begonia, chrysanthemum, cyclamen and primrose are just some of the many other annuals that could technically survive as perennials.

Lily-of-the-Nile, African daisy, daylily, canna, penstemon, New Zealand flax and various grasses and ferns are some of the more familiar perennials. They are too diverse to generalize about, but happen to be among the most reliable of plants for bloom and foliage. Because form and mature size is somewhat predictable, properly selected perennials are unlikely to outgrow their particular situations.

Hobbit’s Pipe

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Jade plant has some weird cultivars.

Good old fashioned jade plant has a few interesting cultivars (cultivated varieties) that exhibit variations of color, texture and form. Hobbit’s pipe, Crassula ovata ‘Hobbit’, is similar to classic jade plant in form and color. It is only slightly lighter green, and only a bit shorter. The succulent stems are just as plump and gray. The small and round-topped clusters of pale pink or white flowers that bloom sporadically are just as unimpressive. What is unique about hobbit’s pipe is the weirdly tubular foliage. Each leaf is rolled into a cylinder, with a hollow tip.

Mature plants do not often get much more than two feet tall and broad, although they have the potential to get twice as large. Because they are more sensitive to frost than other jade plants, hobbit’s pipe should be grown in sheltered spots, or pots that can be moved to sheltered spots through the coldest part of winter. Foliage that is too exposed during the warmest weather of summer can get roasted. Hobbit’s pipe can tolerate a slight bit of shade, so can be happy as a houseplant.

Recycle And Repurpose Overgrown Perennials

60720thumbJust like anything else that gets planted in the garden, new perennials seem to be so cute and innocent. They get even better as they mature. Some grow and spread to impressive proportions. Then . . . some perennials get to be too large. Some get overgrown enough to obscure their own appealing characteristics or other plants. Others get crowded enough to inhibit their own bloom.

Lily of the Nile, which is one of the most common and resilient of perennials, grows and blooms indefinitely. It does not spread too quickly, but eventually creeps a few feet every decade or so. However, if it is too healthy, individual shoots can get too crowded to bloom as prolifically as they want to. Also, shoots that get too close to walkways or other plants eventually become obtrusive.

Anyone who has tried to shear encroaching foliage of lily of the Nile knows that doing so ruins the natural lushness of the foliage. Once scalped, it will stay that way until obscured by new foliage that will be just as obtrusive as the removed foliage. The only remedy is to remove the shoots that produce the foliage, leaving the shoots behind them with adequate clearance for their foliage.

Lily of the Nile shoots are not easy to remove. Their rubbery roots have quite a grip! Yet, once removed, the stout stems can be planted as new plants wherever more new plants are desired. They only need to be watered regularly for the first few months until winter, so that they can disperse roots. If dug and replanted in autumn, they generate roots over winter, and are ready to go by spring.

Overly congested colonies of lily of the Nile, as well as African iris and New Zealand flax, can be dug, split into individual shoots, groomed of deteriorating foliage, and then replanted. Because New Zealand flax has such big leaves, it should be processed in autumn or winter; and its leaves should be cut short so that they do not get tattered and floppy while new foliage and shoots grow.

Bird of Paradise can be divided similarly, but carefully because the shoots are surprisingly fragile. However, giant bird of Paradise is a completely different animal. The tallest trunks eventually begin to deteriorate, so get cut down like trees. Basal shoots are left intact to replace them, so only get divided if obtrusive or overly abundant. Most perennials prefer to be divided after bloom.

Canna and calla prefer to be dug and relocated as their foliage dies back after bloom, just before new shoots develop. However, new shoots often develop before older foliage must be cut back.