Tips for Fast-Growing Plants
There is so much written about fast-growing plants, a lot tends to be just so-so on the crucial “how to.” Mostly you will find short lists of plants, with a few descriptions. Yet there are some tried-and-true horticultural tricks that can help you get the fastest sustainable growth out of plants you need to fix nearly any short-term dilemma.
Here is my experienced take on it all. Keep in mind that though I am a trained horticulturist with years of experience trying to get fast performance from plants in public settings, when I get home I am just a garden-variety gardener who digs his own holes and drags his own hoses. And I want instant gratification as much as the next guy – but on a budget, and with long-term sustainable growth in mind as well.
Last Thing to Consider
Most folks just want to choose and set out reliably fast-growing plants and be done with it. But while it’s true that there are some that grow taller or spread more quickly than others, what you actually put in the ground isn’t the best place to start.
The Internet is loaded with generic lists of allegedly fast-growing plants that may or may not do well in your part of the country. Those “low hanging fruit” searches often don’t take into account year-round rainfall averages, temperature extremes, or soil types. Better to start with your state’s Extension Service literature, which has been tweaked for years by experts with lots of local training, experience and observation.
Also, visit nearby botanical gardens, or at least take a slow drive or walk around older, established neighborhoods near you and look for big plants that have survived a long time without a lot of care, and note how large the plants can get. Always keep in mind two universal truths: Plants only grow as quickly as their roots allow, so do a good job of soil preparation; and many fast-growing plants are relatively short-lived because they are susceptible to root problems, are water hogs, or suffer weather problems such as splitting easily in ice storms.
Landscapers who want shade quickly usually pull from a dependable list of relatively fast-growing trees such as birch, eucalyptus, poplars, Leyland cypress, empress tree (Paulownia), aspen, maples, Japanese zelcova, western soapberry, golden rain tree, Lombardy poplar, sycamore, dawn redwood, sweetgum, honey locust, tulip tree (Liriodendron), and some species of oak, pine, and crape myrtle. Most of these grow pretty well nearly anywhere, but some are limited to specific plant zones.
Some, if not most, of these trees have drawbacks, including leaf or fruit litter, brittle branches that are susceptible to splitting during windy or icy weather, greedy root systems, or invasive “weediness” as they spread easily into nearby areas (some are actually banned in certain states).
A tree or large shrub can be “sped up” by removing some of the lower limbs, then thinning out a few branches from what is left, so more energy will got into what is left.
Shrubs That Jump
Want fast screening from neighbors? Even a short list of evergreen shrubs that grow upwards and fill in quickly can be daunting: Ligustrum, Eleagnus, Photinia, upright junipers, Cleyera, lilac, Loropetalum, Ceanothus, Arborvitae (also called Thuja), some azaleas, Abelia, some hollies, hemlock (can get really big), Pyracantha, Gardenia, yew (Taxus), Japanese yew (Podocarpus), bay laurel, and doublefile Viburnum.
For mild-winter or frost-free areas, throw in rosemary, Ficus, Eugenia, bottlebrush, purple sage (Leucophyllum), guava, natal plum, and Hibiscus. Oh, and don’t forget bamboos, but try to stick with those that grow in slow-spreading clumps, not the invasive “running” kinds!
Just a few of the fastest-growing flowering deciduous shrubs include Forsythia, mock orange (Philadelphia), winter honeysuckle, redosier dogwood, crape myrtle, shrub roses, snowball Viburnum, Hydrangeas, Kerria, redtwig dogwood, Buddleia, Spirea, Persian lilac, American beautyberry, and althea, sometimes called rose of Sharon.
Again, many of these grow only in some parts of the country, won’t tolerate either wet or dry soils, require regular pruning to keep in bounds, or may suffer from insect or disease problems. Some are seriously invasive and may be banned.
Vines used to cover new fences, arbors, or bare walls can be both beautiful and challenging by how fast they grow – or how quickly they can take over everything!
Regardless of where you live, no list of fast-growing vines would fail to include annuals grown from seed such as gourds, moonflower, morning glory, cypress vine, hyacinth bean, and Dutchman’s pipe. And the subtropical areas of Southern California, lower elevations of our Southwest, and along the Gulf Coast have a seemingly endless selection such as sky vine (Thunbergia) and Bougainvillea - too many to get into here but any garden center or Extension Service Master Gardener can help guide you to truly spectacular vines for your area.
Some of the most commonly-grown fast-covering perennial vines include sweet autumn clematis, trumpet vine, cross vine, five-leaf akebia, Boston ivy, coral vine (Antigonon), Wisteria, honeysuckle (especially the non-invasive trumpet honeysuckle), silver lace vine, and climbing roses.
By the way, it is perfectly acceptable horticulturally, and often more attractive through all seasons, to grow two or more different vines on one support.
As with other plants, some of these are VERY invasive, and may be banned in your area. But often there are less aggressive species of each – for example, the much less invasive native American wisteria (Wisteria frutescens) - which are not as aggressive and are okay to plant.
Making Fast Plants Grow Quickly
Some of you aren’t going to like this advice, but it is as true as anything I have ever known, proven over and over in my many years of professional observation and personal gardening experience: A small tree will outgrow a larger one of the same species, every time. This is because a small tree has a larger ratio of roots to top growth, and will get established and start new top-growth much more quickly; a more expensive larger one will just sit there until its roots catch up to the top growth. If it doesn’t die first.
Plants grow only as quickly as their lateral (sideways-growing) roots can support. So the faster a plant can grow good roots, the more quickly it will get established and push its top growth.
Plant It Right
When I want a really fast result, I choose my plants carefully, then set out relatively small ones, with good soil preparation – without overdoing it – and a thick ring of mulch. I water deeply but not too often so roots will grow deep, and hold back on the amount of fertilizer I give them lest I force too much top growth that overwhelms roots. These practices work well with less expense, effort, and plant loss.
Manage Your Expectations – and Create “Baffles”
Choosing good plants, doing moderate soil preparation, light feeding, and regular watering – without overdoing it – yield the best results. But don’t expect miracles. Expect even fast growing plants to take a little while to get started. Anything worthwhile takes a little time; as an old horticultural saying goes, even with the best plants, “The first year plants sleep, second year they creep, third year they leap.”
Meanwhile, if you have an urgent need for shade, screening, or privacy, consider erecting simple or even temporary “baffles” – sections of loose, fencelike screens, using lattice, loosely-spaced fence boards, or even outdoor fabric – right where you need them. Cover them if needed with fast annual vines to buy your permanent plants a little time to get established.