Garden Designers Roundtable: Fantastic Foliage Factoids

Today I’m participating in the monthly Garden Designers Roundtable. Join us as we share our ideas about foliage---what it is and how to use it in the landscape.

Foliage is really the heart of the garden. It cloaks our plants with the colors and textures that create the lush, complex and rich aesthetic experience that we all crave. As a landscape designer I must often rely on my visual memory and employ a descriptive vocabulary to communicate about plants with my clients. Botanists use very specific terminology to identify and classify plants, and leaves have their very own world of weird and wonderful words. Amaze your friends! Astound your children! Impress your mother-in-law! Grow your foliage vocabulary and Trivia Night will never be the same. Here are just a few examples…

First, let’s look at the way leaves are composed.

A simple leaf consists of a single segment, like this Salvia sp., culinary sage:

A compound leaf consists of two or more segments called leaflets. There are at least eight types of compound leaves, but here are two examples that are fairly common. The composition of this Sorbus acuparia, European mountain ash, is oddly-pinnately compound. The leaflets are arranged along a rachis (axis), with a leaflet also present at the tip (terminal).

The Aesculus glabra, Ohio buckeye, has leaves that are palmately compound. There is no rachis present; instead, the leaflets radiate from the apex (upper end) of the petiole (leaf stalk).

Don’t be fooled. The simple leaf of this Acer palmatum, Japanese maple, is cleft (deeply indented, about half way to the mid vein), creating a 5-fingered palmate shape (A hint, there in the Latin name!).

This Chamaebatiara mellefolium, fernbush, leaf is also a trickster. It looks compound, but is just divided (indented all the way to the mid vein).

Round leaf shapes, like these, are orbicular. Nelumbo nucifera, sacred lotus:

Tropaeolum majus, nasturtium:

This Ipomoea purpurea, morning glory has a classic cordate, or heart, shape:

And how about the oblanceolate shape of this kale leaf? And, say, what’s up with the surface there? It’s papillate, covered with pimple-like bumps (Eeeeew!).

Brassica oleracea, Tuscan or - much more funner! - dinosaur kale:

Glossy leaf surfaces, illustrated by this ‘Cleveland Select’ ornamental pear, Pyrus calleryana, are glabrous:

Dull surfaces are, well, dull. No photo needed.

The beautiful, bluish-white waxy coating on this cabbage foliage is called glaucous. By the way, did you know that kales that do not form heads are termed acephala (headless)? What twelve-year-old would not want that word in their arsenal of insults?!

Many, many leaf surfaces have hairs of some sort. Long, short, fine, coarse, wooly, or velvety and they all have weird and wacky names, of course. Here's a photo of one of my plants with its canescent (dense mat of grayish-white [but not curled and interwoven!]) hairs. Behold, Verbascum bombyciferum, giant gray mullein:

Other visual (and named!) foliage characteristics, in addition to composition, shape, and surface, that may be use to describe and/or identify plants, include leaf arrangements, margins, venation, apices, and bases. I’ll save those for another time…

Today, as you visit the posts of my fellow Roundtable bloggers (see links below) or stroll through your own garden, see how many “garden geek” words you can use to describe the foliage that you see. You may even wow yourself!

Resources:

Manual of Herbaceous Ornamental Plants, Steven M. Still

Manual of Woody Landscape Plants, Michael A. Dirr

Vascular Plant Families, James Payne Smith, Jr.

Links to participating Garden Designers Roundtable members:

Andrew Keys, Garden Smackdown

Christina Salwitz, Personal Garden Coach

Debbie Roberts, Garden of Possibilities

Ivette Soler, The Germinatrix

Pam Penick, Digging

Rebecca Sweet, Gossip in the Garden

Shirley Bovshow, Eden makers