Small-space gardening with compact plants

Today’s gardening needs have changed dramatically. Where once families may have lived in suburban lots with outdoor space for generous vegetable and flower gardens, today they might be living in a large house sandwiched on a small lot or an apartment, townhome or condo with a tiny yard or none at all.   

This means that, although there is a strong desire to grow something green, there’s less room and time to do so. Award-winning horticulturist and Penn State alumna Jessica Walliser addressed this issue in her new book “Gardener’s Guide to Compact Plants: Edibles and Ornamentals for Small-Space Gardening.”

If, like me, you’ve ever had plants like bee balm, serviceberry, vibernum or even tomatoes become too quickly mature or overgrown, this book could be the answer to a prayer.

The great news is that growers have developed dozens of varieties of compact plants that are valued for their ability to start small and stay small, even when they reach full maturity.

As a result, they need less maintenance and are perfect for those who want to create a small-scale garden in less time.

Walliser explains that compact plants (also sometimes called dwarves) are not the result of some “funky genetic-engineering technique.” There are three ways that they are created.

The first is that compact plants — generally more common vegetables, annuals and perennials, rather than trees or shrubs — are selectively bred through the tried-and-true plant breeding method of selecting the desired trait, such as a reduced mature plant size, from a group. Those shorter plants are then crossed with other shorter selections. Eventually this dwarfing trait becomes more pronounced and stable.

The second way they are created is by choosing natural genetic variants found in the population, in this case a plant only growing to half the height of the others and propagating it vegetatively (from a leaf, stem or root cutting from the “mother plant”) or via a tissue culture lab. That way the compact trait is present in all future generations.

The third way is by grafting or attaching the shoot system of one plant to the root system of another plant, causing the two plants to grow as one.

The author warns against a further “fake-out” method used by greenhouses and commercial growers to make plants more compact and tidy. That is the use of plant-growth regulators or PGRs.

These are chemical sprays that cause an “artificial and temporary mutation” of the plant to which they are applied. There are questions about the safety of these chemicals being used on edible plants. There is also the fact that once the plants are no longer being treated, they will eventually revert to their normal size and growth habit.

A good question is how to find good quality compact plants at plant nurseries. Here are some offered tips:
* Look for the following language on a plant’s pot tag: “bush-type,” “compact form,” “container-friendly,” “small -statured” and “low growing;” and
* Know the exact Latin or at least full botanical name of the plant, such as “Walker’s Low” catmint or “Tiny Tim” tomato. Words likecompacta, alpinus, prostrata and minor are also clues; or
* Use your cell phone. If you Google, be sure to use reliable information from either a university extension service website or those that are written by industry professionals who work the nursery trade.  A good tip is to add “site:edu” to the end of whatever phrase or word is being Googled; finally
* Ask a knowledgeable nursery employee.

There follows a balanced discussion about how plant breeding and the introduction of various cultivars of plants impacts the health of pollinators. Walliser’s view is that it is important to choose compact plant varieties that are known to support a diversity of pollinators. She claims, in her own garden, to have a mixture of native plants in their straight species form, along with lots of cultivars of native and non-native plants. This creates a habitat with a wide diversity of plants to support many types of pollinators. It is important to choose each plant wisely and steer clear of pesticides.

The remaining sections of the book are very hands-on and practical, with lots of pictures and plant diagrams. One chapter deals with designing with compact plants and includes specific design experts’ designs and their plant lists.

Another talks about what six challenges compact plants can meet, including improving a boring winter landscape, a sloped site, an unsightly view, a colorless garden with no pizzazz, too much shade or one having minimal texture in the landscape.

The book continues on to the best part — 90 detailed profiles of compact plants for the yard and landscape. These begin with specific shrubs like Bobo Panicle Hydrangea and end with herbs, such as Wega Parsley.

The helpful addendum features a contact list of plant suppliers, both here and in Canada.

This excellent compact plant guide, with Walliser’s thorough hands-on approach, is a fine addition to the home gardening library.