Hostas have 30 chromosomes in each of the male i.e. pollen, and female i.e. egg, parts. During the normal fertilization process 30 chromosomes come from the mother and 30 from the father for a total of 60. This is called a diploid or 2n plant which represents 2 sets of chromosomes that make up the genetic information in the resulting seeds and seedlings.

Probably the greatest thing for the Hosta Rookie to understand in all this is that sometimes something happens in the cells of a plant which results in more than 2 sets of chromosomes being present. The most common variation you will encounter is when you hear of plants called tetraploids.

Instead of having 2 sets of chromosomes, tetraploids have 4 sets. This occurs occasionally as a natural mutation so there are plants in the wild who are tetraploids such as the species Hosta ventricosa or triploid i.e. 3 sets, like Hosta clausa. However, people have now also figured out ways to treat hostas with chemicals to create plants with extra sets of chromosomes.

Perhaps the first way was an unintended exposure of hosta plants to the herbicides named Surflan (oryzalin) and Treflan (trifluralin). Following this exposure, the nursery person noticed a change in the physical characteristics of hostas.

A second, much more common way that tetraploid hostas have been induced is through exposure to certain plant hormones during the tissue culture process. We will cover tissue culture in greater detail later but suffice it to say that part of the process involves the use of plant hormones such as indole butyric acid (IBA) and naphthalenic acid (NAA). For some reason, certain hostas exposed to this treatment will develop tetraploid plants.

Daylily (Hemerocallis) breeders have been developing tetraploids for several decades. They often use a chemical called colchicine which is an extract from the fall crocus, Colchicum speciosa. It appears that this chemical does not have the same effect on hostas, however.

So, why are we so interested in tetraploid plants? Well, not only do they have a unique genetic makeup, tetraploid plants also generally have some unique physical characteristics including:

1. Plant Size – Tetraploid plants tend to be a bit smaller than diploid plants of the same cultivar and have shorter leaf petioles. However, this more compact structure makes for a denser plant habit.

2. Substance – Compared to a diploid plant, the tetraploid has thicker cell walls and larger stomata guard cells resulting in a leaf with thicker substance. The petioles are thicker also.

3. Flowers – This is the area where the daylily people have made big advances with tetraploids. The flowers of these plants are larger and have thicker petals or, in the case of hostas, tepals. Also, flowers of tetraploids produce larger pollen grains than their diploid counterparts.

4. Flower Scapes – The flower stalks will be shorter and thicker on tetraploids. Often the flowers on the scape will be compacted together in a denser arrangement.

5. Seed Pods – On tetraploid hostas, the seed pods will be shorter in length and thicker.

6. Growth Rate – In general, tetraploid plants will have a slower growth rate than diploids of the same cultivar.

7. Roots – In keeping with the general trait of these types of plants, the roots of tetraploids will often be shorter in length.

8. Leaf Color Variegation – Tetraploids will generally have wider marginal variegation but narrower medial or center variegation.

9. Chloroplasts – Chlorophyll is, of course, the green pigment. The chloroplasts are the structures where chlorophyll resides and where photosynthesis takes place. In tetraploid plants, there may be up to twice as many chloroplasts as in the diploid plant.

10. Leaf Surface – For cultivars with corrugations or ripples on their leaves, tetraploids tend to be more pronounced.

CAUTION: Now that we have told you all the characteristics that may indicate a plant is a tetraploid, be aware that it is not that simple. Even if a plant has ALL of these traits, the only way to know for certain that the plant is a tetraploid would be to subject it to a bunch of different laboratory tests. Also, it would take a person well-trained in the science to examine the morphology of the plant and, perhaps, do some cross-breeding to tell for sure. Most of what you hear about a plant’s tetraploidy will be a matter of opinion. It may well be truly tetraploid but not proven yet by analysis.

I think some of the confusion comes from a couple of factors. First, in their effort to make a quicker return on their investment, some nurseries sell tiny, little TC plants in two inch pots. Of course, it may take a year or two for these to grow to the size of a single division taken directly from a mature mother plant. But, they will eventually catch up.

If for example, both plants came from an H. ‘Sum and Substance‘ mother plant, they should both eventually grow to the same mature size given similar growing conditions. It may take the under-sized TC plant a little longer because it started as a smaller plant. If the TC plant is grown to a larger, more typical,  size at the nursery before it is offered for sale, there should be little or no difference between it and a similar size hand-made division. When both plants are grown under similar light, fertilizer, water and other conditions, they will be virtually identical when they reach mature clump size.

Another point of confusion may come from the fact that there seem to be a lot of sports produced during TC. Sports are “spontaneous” changes in the morphology i.e. external traits of a plant. These kinds of changes tend to happen to hostas more than most genera of plants. Whether in the wild populations, in gardens or nurseries, it is quite common to find otherwise solid colored hostas suddenly developing a set of variegated leaves. Or, for variegated plants to “revert” back to the solid base color.

If the new characteristics of the sport are unique or “outstanding”, this changed division may be separated from the mother plant and grown on. Providing that the changed foliage color “stabilizes” over a period of years, the plant may be introduced as a new, named cultivar. The process of finding these changed plants in the garden or nursery is called “sport fishing”.

Finding new cultivars from sports in a random garden is fairly unusual. After all, even the largest of all hosta gardens such as those at Wade and Gatton Nursery in Belleville, Ohio will have “only” about 3,000 different cultivars of hosta. The average hosta enthusiast may have 300 to 500 cultivars in his or her garden. Therefore, the odds of finding an outstanding new sport are rather slim.

In larger tissue culture labs, the number of worthy sports that are discovered is usually way, way above average. There are basically two reasons for this to occur.

One factor is that part of the tissue culture process is to expose the developing plantlets to a type of naturally occurring plant hormone called a cytokinin. In nature, cytokinins are involved in the development of new buds and in hostas, this includes those buds that produce new sets of leaves from the crown. This is a totally natural process, however, in the TC lab, it is pushed at an accelerated rate. So, the TC plants are producing many, many, many more buds in a relatively short time as compared to their counterparts growing in the garden.

The other factor in TC is that, over a period of 6 to 12 months, literally tens of thousands of an individual cultivar may be produced. So, in a greenhouse situation, there may be say, 10,000 H. ‘June’ growing side by side. How many gardens would a sport fisher have to visit to see this many of one cultivar?

Given the exposure to the plant hormones that stimulate buds and the creation of huge numbers of the same cultivar in a short time and space and you can see that the possibilities for finding outstanding new sports is pretty high. No wonder people such as Hans Hansen and Clarence (C.H.) Falstad who work at major TC labs have registered many outstanding new cultivars of hosta in the past couple of decades.

In the end, the key thing to remember is that all the “non-sports” that come out of the TC lab should be perfectly fine and just exactly like the mother plant cultivar. Quality control at the lab and greenhouse should separate the sports (good and bad) from those that are shipped to the ultimate consumer…the home gardener.

Want to learn more about hostas, the Number 1 selling genus of perennial plants? Well, we are in the process of writing several eBooks about hostas, their care and use in the home landscape. These are part of our “A Rookie’s Guide to…” series of landscape gardening ebooks.

The first in the collection, A Rookie’s Guide to Hostas, Hostas, Hostas, is now available in .PDF and .ePUB formats at Lulu.com. For more on this and our other ebooks…give us a click.

Seedlings of the boxelder tree (Acer negundo) have prominent “leaves of three” and are often mistaken for poison ivy.  As they grow, however, they soon form a tree-like central stem and stand upright on their own. Poison ivy (Toxicodendron radicans) is a vine and needs something upon which they can grow such as a tree trunk or fence to raise their foliage toward the sun.

Douglas fir (Pseudotsuga menziesii) is not a fir (Abies species), however, Kirk Douglas was the star of Sparticus. Douglas fir was named after the plant explorer, David Douglas. It is a tree that somewhat resembles a hemlock (Tsuga canadensis) thus the genus name, Pseudotsuga. The specific ephithet, menziesii, is in honor of another famous plant explorer, Archibald Menzies. Gee, there some of these scientific names actually do have some rhyme and reason.

Dutch elm disease killed primarily American elms (Ulmus americana). The disease is believed to have come from Holland on some veneer wood, thus the name. You would be amazed at how many people think that it attacks “Dutch” elms when there is no such thing…as far as I know, anyway.

Oregon grape holly (Mahonia aquifolium) is not a holly (Ilex species). It may be from Oregon but the purplish fruit it develops are not good for making wine…at least not in the classic sense. I know that people make wine out of all kinds of stuff including dandelion greens so who knows.

The roots of black walnut trees (Juglans nigra) form a substance called juglone that is poisonous to many other plants. Tomato plants growing near walnut trees will often wilt and die in late July. However, many other plants do not seem to be affected. For those that are impacted by juglone, the chemical gets into the roots and soon gums up the water carrying vessels. Thus, the plants start to wilt during the hottest part of the summer when water demands are greatest.

Our beloved, Hostas used to be called Funkia after a guy named Heinrich Christian Funck. There was a rock group called the Funkadelics but I don’t think they had anything to do with hostas. Hostas were also called Plantain Lily but that too has been largely abandoned by the gardening public. Today it is simply, Hosta.

All azaleas (Rhododendron species) are actually rhododendrons (Rhododendron species). Only a small number of rhododendrons are azaleas. How do you tell the difference? Heavy duty fans of the genus have several ways they use to divide the thousands of species and cultivars of rhododendrons. However, one simple delineation is that rhododendrons generally bear their flowers at the tips of their stems. Azaleas generally have flowers all along the length of the stem too.

Spider mites are not insects. Insects have six legs. Spiders and their relatives have eight. Eight is Enough was a television program back in the 70’s. Perhaps the key here is to know that many of the commonly used insecticides are aimed at…guess what…six legged creatures. They may not be effective against the eight legged critters that are sucking juices from our plants. You can learn more about insects and even help us identify some…Name That Bug.

Staghorn sumac (Rhus typhina) has red berries borne at the tips of the branch. Poison sumac (Toxicodendron vernix or Rhus vernix) has white berries borne along the stem. Chuck Berry is one of my favorite singers. Poison sumac is almost always found in wet, swampy areas while staghorn sumac is usually found in higher ground.

Grape hyacinth are not hyacinths. They are in the genus Muscari. Their fruit makes lousy wine. See Oregon grape holly above for a discussion of wine makers.

Bats have their young during the first two weeks of June. The runt of the litter is always named Robin.

Yellowjackets, wasps and hornets live just one year. Only the queens survive the winter and re-establish new nests the following spring. The rock band, “Queen” minus their wonderful, late lead singer, Freddie Mercury, maintains a nest in England.

Hostas are often called “shade loving” plants. For the average gardening public, this helps them to understand that these plants are adapted to growing in the shade. However, for more advanced hobbyists or professionals, this is a misnomer.

All vascular plants live by a process called photosynthesis. They capture the energy from the sun and, unlike animals, they make their own food. For photosynthesis to work, a plant must have five things including light, water, nutrients from the soil and the air, chlorophyll and suitable temperature. The minimum levels of each of these factors required may vary from species to species but they all must be present in certain amounts for photosynthesis to take place in that plant.

For a plant to be truly a “shade lover” would imply that it could complete photosynthesis in a dark closet. That is clearly not the case here, so hostas are actually “shade tolerant” plants which can survive and often thrive at low (but not zero) light levels. In fact, most of them will do best in more sun but, to keep them aesthetically pleasing, we sometimes have to make concessions.

When people classify themselves as either a “shade” or a “sun” gardener, they often act as if we should all understand exactly what they mean. Here again, those terms can bring to mind a wide range of light conditions.  We will define garden light levels as follows:

_       1. Full Sun – Plants that are designated as full sun plants are usually those that are native to open, prairie or swampy type environments that support few or no trees. They are conditioned to having sunshine hit their leaves from sunup in the morning until sundown in the evening. That is the accurate definition of FULL SUN!

However, over the years, gardeners and horticulturists have come to understand that these plants can still perform adequately while being exposed to less than total sunlight all day long. The common rule of thumb is that you need a MINIMUM of around 6 hours of direct sunlight per day for these plants to thrive. Full sun plants that get less than that amount will develop stems that are overly long and weak i.e. etiolated, which tend to fall over. Such plants will not flower well and will not be as vigorous as those getting more sunlight. Just remember that those 6 hours are a minimum and more would be better.

_       2. Shade – So, if 6 hours is needed for full sun, it would be a simple conclusion to assume that shade plants can live and even thrive in less than 6 hours. Again, although we talk about shade as if it were a single unit, the reality is that there are generally considered to be 3 categories of shade in the home landscape.

_          a. Light Shade a.k.a. Dappled Shade or Partial Shade – This is the situation where you have just a few trees in the landscape or when you have trees with small leaves such as honeylocust. As the sun passes over the horizon, the plants in the shaded areas may receive a total of up to 5 or 6 hours of direct sunlight. The key is that they will get it a few hours here, an hour there and another hour later. It will not be 5 or 6 hours in a row. This will be a great growing environment for our shade tolerant plants.

_          b. Medium Shade a.k.a. Open Shade or High Shade – This is the situation when you have many large deciduous trees such as oaks where the bottom branches may be 20 or 30 feet off the ground. As the sun passes over head, the plants beneath may only receive direct sunlight for a couple of hours total during the day but the environment is generally “bright”. In this landscape, a person could take a seat under the trees and easily read a book but rarely have direct sunlight penetrate onto the paper. This is also a very good environment for shade tolerant plants.

_          c. Deep Shade a.k.a. Dark Shade or Dense Shade – Deep shade will occur beneath evergreen trees such as pines or spruce or deciduous trees with large leaves such as Norway maples. This will also be the case close to the north side of buildings. Under these conditions, as the sun moves across the horizon during the day, no direct rays will strike the plant. The only light will be that which is reflected back into the dark from the surroundings.

This is a very difficult environment for growing shade tolerant plants. Hostas and others will usually survive these conditions but they will not thrive. For instance, hostas growing under the first two levels (a & b) of shade will add new divisions to the clump at a rate consistent with that expected of a particular cultivar. Those same hostas grown in the deep shade will multiply at a much, much slower rate, if at all. They will also develop thinner and, often, fewer leaves than would the same cultivar planted in shade levels a and b.

Native Region for Hosta Species

The first documentation of the genus, Hosta, came from a medical doctor with the Dutch East India Company named Engelbert Kaempfer (1651-1715). Dr. Kaempfer was stationed in Japan but was segregated on a tiny island and was not permitted to travel around on his own. Somehow, he was able to get local Japanese to bring him plants and he made a drawing of one that was later identified as Hosta ‘Lancifolia’. Unfortunately, he was not able to bring back any live specimens.

Although, by far, most species of hostas come from Japan, the first two plants to be introduced into Europe came from China. It is believed that Hosta plantaginea was first grown in Paris at the Jardin des Plante in the mid-1700s while Hosta ventricosa found its way to a private garden in London about the same period. According to Zilis (2009), Hosta lancifolia, H. plantaginea, H. ventricosa and H. ‘Fortunei’ were the first hostas to be introduced into Europe.

Two of the primary early explorers who were later able to actually bring hostas back to Europe from Japan were Philip von Siebold (1796-1866) and Robert Fortune (1812-1880).

Von Siebold was a medical doctor from the Netherlands who traveled to Japan in 1823. He was able to acquire many Japanese plants that he later brought back to Europe. He returned on a second trip in 1859 and had more freedom to roam around the islands to collect plants. Among these were several species of hosta. Back in Holland, von Siebold was instrumental in setting up the first botanical garden at the University of Leiden.

Perhaps the most common hostas of all belong to the large, blue-green leaf species that bears his name, Hosta sieboldiana. (Remember that this might be changed to Hosta ‘Sieboldiana’ in the future.) It comes from Honshu Island in Japan. The other plant, Hosta sieboldii, is a small plant with narrow leaves that have a slender, white margin of variegation. There is also some debate as to whether this is a true species but, so far, it remains listed as such.

Robert Fortune was one of the first European plant explorers to be allowed to wander around China to collect plants. He was educated at the Edinburgh Botanic Garden in Scotland and worked for the Royal Horticultural Society at their gardens in Chiswick in England. They sponsored his expeditions to gather exotic plants to bring back to Great Britain.

In addition to rhododendrons and many, many other plants, he also brought hostas back to Europe. One was given his name as a species, Hosta fortunei but Schmid (1991) found no evidence that this plant actually came from the wilds so it was reclassified as a cultivar, Hosta ‘Fortunei’. This confusion occurred probably because the people back in Europe figured that the plants were from wild populations. In reality, the local Japanese people who procured some of the plants for the explorers may have gotten them from private or temple gardens where they had been growing in cultivation for hundreds of years.

Modern day plant explorers continue to periodically scour Japan, Korea and China in search of new species of plants that might be prime for introduction into America, Europe and other countries. In fact, in 1985, an American horticulturist, Barry Yinger, was exploring in remote areas of South Korea when he discovered two new species of hosta. One of them was named in his honor as Hosta yingeri and the other was  H. jonesii. The second new species was named for botanist Dr. Samuel B. Jones of the University of Georgia who helped Yinger identify the plants.

To learn a lot more about the genus, Hosta, its species and cultivars along with the people who have made hostas the Number One selling perennial in the U.S. please checkout our new eBook – A Rookie’s Guide to Hostas, Hostas, Hostas.

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