The base or primary leaf color is defined as the color that occupies at least 60% of the surface area of the plant. Secondary colors, usually involved with variegation, are those colors that occupy 40% or less of the surface area.

In the landscape, we are concerned with visible light which is that part of the spectrum of light waves that is reflected back to our eyes from a plant. In design, we use these colors to form combinations that are pleasing to the average human's perceptions.

Basically, the color in hostas is due to the amount of chlorophyll (green), carotene (yellow) or waxy bloom (blue) in the leaf. The complete absence of chlorophyll results in white being reflected from the leaf.

Of course, some plants have only one color covering 100% of the leaf surface. These are often called monochrome colors. A distinctive secondary is not present so these are considered non-variegated plants.

Colors of hosta leaves can change for a variety of reasons. These include concepts such as stability, sporting, surface effects and seasonal color changes.

The American Hosta Society recommends using the Royal Horticultural Society Colour Chart for accurate hosta leaf color determination.

Typical base leaf colors in hostas would include:

In the wilds of Japan, Korea and China, hosta leaves are various shades of green. With that said, it must be understood that there are many different variations of this color found in cultivated hosta plants. According to the AHS cultivar registration form, hostas should be described as light green, medium green or dark green.

Of course, these are the "official" color categories but nursery catalogs and gardeners may use other terms to describe their particular shade of green. For example, chartreuse is often used to describe the color of cultivars such as H. 'Sum and Substance' and H. 'Chartreuse Wriggles'. A few hostas with very, very dark green leaves may be described as "black" at times.

Throughout the hosta world plants like H. sieboldiana 'Elegans' are almost universally referred to as "blue" hostas. However, such plants are all technically, blue-green in color. When registering a new hosta, The American Hosta Society recommends that you use terms such as slightly blue-green, medium blue-green and intensely blue-green to identify this leaf coloration. Some references or catalogs may talk about blue, blue-green, gray and gray-green to describe these plants.

As mentioned before, all the species hostas are green. The difference here is that some hostas have developed a waxy coating over the green which reflects blue light. Thus, we see them as blue-green. If you rub the leaf of a blue hosta between your fingers and remove the wax, it will quickly show the green below.

The wax on the leaf surface is at its thickest and best in the cool of the spring. As the summer progresses, the heat of the sun and pounding rain, will cause the wax to wear off. Plus, hostas appear to produce less wax as the summer advances. So, by autumn, many "blue" hostas become green hostas. This doesn't hurt the plant but, if you wanted the blue color to work as a complement to nearby yellow plants, you will lose that effect late in the year.

Hostas that develop a very thin covering of wax may lose it very early in the season. These plants end up spending most of the summer as green hostas and may be classified as either base color category (blue-green or green) depending on the reference or catalog.

Mr. PGC Comment: The blue-green cultivar H. sieboldiana 'Elegans' was developed in 1905 and has since become one of the all-time classics in the hosta world. At a recent meeting, I heard the hosta Registrar mention that around 400 new cultivars had been registered the previous year. Of those, over half had 'Elegans' in their background. There are a huge number of large blue hostas out there, folks!

Yellow Leaves - How many times have you heard a hosta referred to as being "gold" in color? Well, as with blue, that is not an official designation. If you look at a color wheel, you will not find gold but you will find yellow as a primary color and that is the proper descriptive term. The registration form recommends the use of greenish-yellow, pale yellow, yellow and golden yellow to describe new hostas.

Yellow color in hosta leaves is the result of a mutation called an inhibitor gene which causes the plant to produce a very low level of chlorophyll in certain chloroplasts.  Depending on the amount of inhibition that takes place, the leaf color will vary from chartreuse to a very dark, rich yellow or "gold".

White Leaves - Although most gardeners might not think of it, white can also be a base color for hostas (although NOT included on the AHS registration form).  A hosta may have 60% of its leaf surface white but, of course, a plant cannot be totally white in color. Occasionally, a seedling will emerge that is entirely white but once the energy from the seed is spent, it will die. Without the green chlorophyll molecule, such plants will not be able to carry out photosynthesis and feed themselves.

However, certain variegated plants come close to being totally white but still have enough green chlorophyll so they are capable of supporting themselves. Such plants will generally have very thin leaf substance and will grow more slowly than their fully green species forms. They are also sometimes difficult to site properly in the garden. If they are exposed to too much sun, the thin leaves will lose moisture rapidly and "burn" easily. Finally, there is some evidence that slugs prefer to chew on leaves with thin substance so many of these types of hostas look pretty ratty by the end of the summer in typical home gardens.

The official descriptive terms for these types of hostas would include greenish white, creamy white and pure white.

Mr. PGC Comment: The problem is that some of these mostly white hostas are SPECTACULAR looking in the early spring before the heat of the summer and slugs do their thing on them.

 
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