Dr. Bob Gilbert – Columnist
About 30 years ago, just 20 hosta varieties were in the market. Then experts were telling us that hostas were perfect for the shade. Today, there are now over 6000 and about 300 are in the market. This amazing explosion in the number of new plants has happened mainly because contemporary plant explorers have combed the orient looking for and finding new species. The pure species count is now about 45 with a few in dispute. In addition, hostas are easy to hand pollenate even by amateurs and their seeds are fairly easy to germinate. So, this interjection of new genes into the hosta gene pool has added great and exciting variations. It is also curious that professionals’ breeders have learned to misuse pre-emergence herbicides to induce hosta mutations. This subject would require additional research.
Let’s cover a few basic known hosta facts:
• Hostas will not grow successfully in full shade. They like dappled shade. Dappled means small patches of direct sunlight mixed with shade. Allan Armitage commented in his fabulous book “Herbaceous Perennials,” “Daylilies may be the king of the sun but unquestionably hostas are the emperors of the shade.” His statement published in 2008 is no longer completely accurate. Hostas require some morning sun and afternoon dappled shade.
• Hosta will not tolerate drought. After a year in full shade and/or drought the plant will all but disappear.
• Hosta plantaginea, native to China, is the only pure hosta species that will grow in full sun. Hostas are sometimes called Plantain Lilies because a few resemble one of the Plantain weeds. They belong in the asparagus family. Plantaginea is the only species whose flowers have a scent. It also has very large leaves. It has been difficult for hosta breeders to use Plantaginea for cross pollinate because its blooms open from 4 to 5 p.m. All other hostas blooms open between 7 to 8 a.m. Any hosta with a scent and that might stand little more sun has some plantaginea genes.
• It is not true that blue hostas like more shade and yellow hostas like more sun.
• All blue hostas originated from one species, Hosta sieboldiana. It grows at high elevations in Japan. Crosses have been made between it and heat tolerance hostas to achieve a blue hosta hat that will grow in warmer climates. Sieboldiana has large puckered leaves that are often described as sear suckering. All leaf puckering is the result of Sieboldiana genes. Some have a waxy silvery or glaucous coating on the leaf surface.
• Variegations or patterns in hosta leaves are the result of a mutation within the leaf. All hosta leaves have three layers. Mutations occur in layer #2. Variations-mutations may occur in the center of the leaf or on the edge or both. Leaf colors of blue, green, yellow and white can occur in a multitude of patterns. Also, there may be color streaks. Streaked varieties are unstable meaning the pattern will likely disappear as the plant matures. Some varieties that have bright yellow leaves and will lose the yellow as the plant gets older.
• When hosta are propagated from seed most will emerge with pointed leaves and are called juveniles. They may change as they mature. When you buy a very young hosta in a pot it likely will not look the same after it matures.
• Hosta clumps can be dug and separated to increase numbers any time of the year. The more leaves left on a division the faster it will recover. Every leaf stem has a dormant bud at its base just above the roots. With a knife a single stem can be separated from its neighbors leaving a stem, a single leaf, a dormant bud and some roots. Using this technique, you could create dozens and dozens of new plants. However, it would take 2-3 years for these plants to mature.
• Red stem hostas are called Rock Hostas. They grow on cliffs on an island off the coast of Japan. They are quite attractive and often have white on the under-side of the leaf. They all have pointed leaves.
• Dwarf hostas all come from an island off the coast of Korea. These small hostas are called Mouse Ears. They typically have very thick leaves.
• Hosta are described and lumped together by size, dwarf-less than 10”, small-10-15”, medium-15-22” and large-over 22”.
Probably the most refined plant society journal is published by the American Hosta Society. Its journal has amazing photographs as well as great articles. For example, the current issue as 70 full color photos of varieties well identified. With it you can keep updated on the new varieties. The society has a huge membership. They conduct a membership hosta popularity survey every year. For many years Hosta “June” has been voted most popular followed closely by Hosta “Sagae.”
Hostas were first named Funkia in honor of a German botanist Henrick Funk. The current common name Hosta is in honor of an Austrian botanist Nicholas Host. This means that we mispronounce hosta? My young nephews and nieces thought it hilarious that I grew funky plants.
Hostas have a vast audience that includes slugs, snails, voles, rabbits, deer and humans. Deer are the worst. My expert gardener and late friend Sam Blasingame grew large numbers of hostas successfully. He applied Deer Away monthly and he never had a problem until one month they forgot to use it. All of his hostas were nibbled down to the ground after years of survival. They will grow back because the roots were left intact and with the reuse of Deer Away.
Voles are interesting. They look very similar to mice. They use mole tunnels and only feed on plant roots especially hostas. Moles only feed on worms and grubs. There is product called Rozol Vole Bait. If used regularly following the manufactures directions it will eliminate voles. I have heard a very serious hosta nurseryman Tony Avent say that Rozol Vole Bait is 100% effective if used according to directions. It is pet friendly but best to read the fine print.
Slugs and snails are attracted to beer. If you can share a pie pan of beer it will fill up with drunken dead slugs. This is a safer method than using slug pellets that are not pet friendly.
Hostas are relatively free of diseases. There are several hosta viruses. When these are found the affected plant(s) should be destroyed not put in the compost bin.
With a little thought you can have a garden full of amazing hostas. They are easy to grow. The main thing you need to remember is most hostas will not grow in full sun and will not survive in very wet or very dry soil. At division time they make great pass along plants. Every garden with a little shade should have a little funk.
Dr, Bob Gilbert now living in Franklin is co-founder of Smith Gilbert Gardens in Kennesaw, Ga.