Reassignment

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There is quite a bit of open space in some parts of the landscapes. It is not as if the landscapes are lacking much. There just happens to be a few spots where a bit more could be added. This expanse of healthy English ivy was already appealing, but lacked interest.

There is also quite a bit of spare plants out and about in the landscapes. It is not as if there is anything wrong with spare plants. There just happens to be too many of them. These cannas got overgrown and crowded within their original colony in another landscape, so needed to be divided and thinned out.

We are not a so-called ‘landscape’ company, which profits from the removal of some plants, and the installation of others. There is no incentive to dispose of as much vegetation as we could bill a client for. Nor is there any incentive to install as many new and expensive plants as we could fit into any available space. It is not a ‘business’.

To the contrary, it is in our own best interest to exploit resources that are already available to us. For example, when we thinned out these crowded cannas from one situation, we reassigned them to other situations where they could grow and become assets to their new landscapes. Also, viburnums that were removed from one site were reassigned as hedges in other situations.

We will be doing more of this sort of reassignment now that the weather is cooler and rainier, and the plants that will get relocated are dormant. Carpet roses that must be removed from the boundary of a playground because they are too thorny will be relocated to a broad roadside, where they can grow wild. They will be replaced with lily-of-the-Nile that is crowded elsewhere.

Division Renovates Tired Old Perennials

91204thumbAutumn is a time for planting partly because it is when many plants are beginning their winter dormancy. They are, or will soon be, less active than they would be at any other time of year. Some may not start to grow again until after winter ends. Others will want to secretly disperse their roots through the rainy winter weather, while merely appearing to be dormant from above the soil level.

That is why autumn is also the best time for division of many types of perennials. Such perennials should be adequately dormant to not be bothered by the process of getting dug and divided into smaller parts, then replanted. They actually prefer to get it done sooner than later, so that they can slowly disperse their roots through cool and rainy winter weather, and be ready to grow in spring.

Divisions is often done to renovate bulky perennials that have become overgrown, shabby, or too crowded with their own growth to bloom well. Some of the more vigorous perennials may benefit from division for renovation every several years or so. Many complaisant perennials may never benefit from division. Of these, some might be divided merely for propagation of more of the same.

Japanese anemone, bergenia and other perennials that bloom in autumn and winter should get divided later, after bloom. Like perennials that get divided now, they tend to recover and efficiently disperse roots before spring. However, they may need to be watered a bit more than typical if the weather gets warm and dry early next year. Their schedules do not coincide with local climates.

Lily-of-the-Nile, African iris and New Zealand flax can be divided into individual shoots, even if a few shoots get planted together in clumps. Entire plants do not need to be dug if it would be easier to merely pluck a few outer shoots from the perimeters of congested parent plants. Black-eyed Susan and Shasta daisy can be divided into clumps of several dormant basal rhizomes and roots.

‘Pups’, or sideshoots, of agaves and some types of yuccas can be carefully pried from their parent plants without disturbing them.

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.

Finish Transplanting Before Winter Ends

90220thumbAutumn is for planting; and for good reasons. It is the beginning of dormancy for almost all plants, including evergreens. It precedes cool and rainy weather that inhibits desiccation until new roots are able to disperse sufficiently to sustain new plants. Some plants need to be in the garden in time for winter chill in order to initiate bloom. However, not everything should get planted in autumn.

Winter is the best season for some plants. Many summer blooming bulbs get planted in winter because they are likely to start growing prematurely and get damaged by frost if planted in autumn with spring bulbs. Some perennials that are slightly sensitive to frost may get planted after average frost season so that they can bulk up enough to be more resilient to frost by the following winter.

Besides new plants that are purchased from nurseries to be planted in the garden, there are plants that are already established in the garden that might need to get dug, divided, and then planted back into the garden, or shared with friends and neighbors. Some might need to be transplanted because they are crowded or in the way of something. These present a different set of variables.

Once divided and transplanted, grasses, New Zealand flax, lily-of-the-Nile, African iris and other stoloniferous perennials (that spread by creeping stems known as stolons) are more susceptible to rot than nursery grown plants, because so many of their roots get severed. Even if aggressively pruned while getting divided and transplanted, shrubby plants, like lilac and forsythia, are more susceptible to desiccation than nursery grown plants, simply because they lack sufficient roots.

If divided or transplanted through winter rather than autumn, plants get a few weeks of cool and rainy weather to settle and disperse their roots, but do not have enough time to rot or desiccate before the weather gets warm enough for them to resume growth and recover resiliency. Perennials that get cut back in the process spend less time looking shabby before new growth develops.

Propagation Of Perennials By Division

80718thumbAutumn is for more than planting. It is when most of the aggressive pruning gets stared. It might be the best time to work with compost and conditioning the soil. Bulbs get planted. Gutters get cleaned. Leaves get raked. Perennials get groomed. We might think of it as a time of slowing down after such a busy summer, but in many gardens, autumn is just as busy with seasonal chores.

Autumn is when many of the spring, and some of the early summer, blooming perennials get divided. That means that they get dug up, split into smaller parts, and then replanted. Because there will be more smaller plants after the process than there were bigger plants before the process, some should get planted over a larger area, in other parts of the landscape, or shared with friends.

Not all perennials need to be divided annually, and some may never need to be divided at all. Perennials that bloom in autumn or winter, such as Japanese anemone and bergenia, get divided in spring, since they will have plenty of time to recover from the process to bloom on schedule. Black-eyed Susan does not likely care if it gets crowded, but can get divided simply for propagation.

Lily-of-the-Nile should be divided if it gets too crowded to bloom well. Division allows more room for the individual shoots to grow and bloom as they should. However, because it takes a while for newly divided shoots to recover, they should only be divided every few years or so, and only if they happen to be getting crowded. African iris gets divided if overgrown plants are looking shabby.

It is not always necessary to dig entire plants. If dividing New Zealand flax just for propagation, it is easier to pry the desired number of side shoots from a mature clump, without digging the main part of the clump. Agave pups might be (very carefully) pried off of larger rosettes just to keep the main rosettes neat. Black-eyed Susan and other deciduous perennials get divided while bare.

Division Is Equal To Multiplication

70809thumbMathematically, division is the opposite of multiplication. Horticulturally, they are the same. Digging and splitting overgrown perennials to propagate them is known as ‘division’ because it divides many rooted stems or rhizomes of one plant into many new plants. Division is a form of propagation; and propagation is commonly known as multiplication. So, we divide plants to multiply them.

Autumn is generally the best time for panting. It is after most of the warmest and driest weather, and just before the cool and rainy weather that keeps newly planted plants from getting too dry. It seems obvious that autumn would also be the best time for division. However, a few perennials that are dormant or mostly dormant by the middle of summer can be divided now for an early start.

Bearded iris may not look dormant with their leaves still green, but they are about as dormant now as they will get. If divided now and allowed to slowly disperse roots through the remainder of summer, they can prioritize the production of new foliage when they come out of dormancy in autumn, like they would do naturally. Like many perennials in mild climates, they grow through winter.

Once dug, the plump rhizomes need to be separated from the old shriveled rhizomes that they grew from. For most, the best segments of rhizome are between the leafy tips and the stalks of the flowers that bloomed earlier this year, although it may not be easy to see where floral stalks were attached. The older sections of rhizome behind the flower stems are probably shriveled already.

The freshly divided segments of rhizome should then be groomed of deteriorating old leaves. Remaining green leaves can be cut in half to remove drying tips. Rhizomes then get replanted just below the surface, with the perpendicular fans of foliage standing upright. The main difficulty with dividing iris now is that they will need to be watered until the rain starts late in autumn. Bergenia, lily-of-the-Nile and a variety of perennials with big rhizomes get divided in a similar manner.

Avens

80509Wow, this is quite old school. Is it making a comeback? That would be nice. Avens, which is also known as Chilean avens, Geum quellyon, is an old fashioned perennial relative of the strawberry. Instead of producing fruit, it provides handsome yellow, red or coppery orange flowers that look something like small single, semi-double or double anemones, but can bloom through most of May.

Although perennial, avens do not last forever without some degree of help. After the first season, most of the slightly ruffled and hairy foliage dies down during the colder part of winter. New foliage and bloom develop in spring. After the second or third year, and every few years afterward, mature plants should be divided before or after bloom. Pups are more vigorous than the parent plants.

Happy avens gets as high and wide as a foot and a half. Much of the height is in the branched floral stems, which might need to be staked if they get too heavy with bloom, or are in a breezy spot. Most of the mounding foliage is basal. A bit of shade is tolerable and actually preferred to hot situations. Soil should be rich and well drained. Avens plays well with others in mixed perennial beds.

Perennials Can Divide And Conquer

10810Along with all the bare root fruit trees, roses and cane berries, nurseries also stock bare root perennials like strawberries, asparagus, horseradish and rhubarb. They are so easy to plant while dormant. They recover from transplant through spring, and by summer, should be growing as if they had always been there. Although, if they had always been there, they might be crowded by now.

Yes, many but not all perennials eventually get crowded. Strawberries spread by runners, so are easily plucked and transplanted to avoid overcrowding, as well as to propagate more productive plants. Asparagus are variable, so may not get crowded for decades. Horseradish and rhubarb may not mind getting crowded, but could be more productive if individual plants have their space.

For example, crowded horseradish plants produce many small roots. If dug, split apart, and replanted with more space between individual plants, the individual roots get much larger. Separating the roots, which is known as ‘division’, also produces many more new plants. Mature rhubarb plants may not mind being crowded, but are often divided simply to propagate new productive plants.

Division of these sorts of perennials is typically done while they are dormant through winter. If that sounds familiar, it because it is the same reason why these sorts of perennials are available as bare root stock. They get processed while they are unaware of what is happening, and wake up in their new and better situations. Many defoliate while dormant. However, most are evergreen.

Ornamental perennials like lily-of-the-Nile, African iris, New Zealand flax, society garlic, torch lily, lily turf and acorus grass are all good candidates for division if and when they become overgrown. So are most aloes, some terrestrial yuccas, several ferns and some of the more resilient clumping grasses. Agave pups can be dangerous, but really should not be allowed to get too crowded.

Division might be as simple as taking a few pups or sideshoots from a large clumping plant, or as involved as digging an entire large plant to divide each individual shoot. More often, large plants get dug and split into a few smaller clumps of many shoots. New plants should be groomed of deteriorating foliage. The long leaves of New Zealand flax should be cut in half to avoid desiccation.