Saturday, February 4, 2017

Growing Daylilies Part 1

Growing Daylilies
Part 1
The Basics

There is no plant easier to grow than the daylily...provided you select the right daylily cultivar for your area or needs. While many daylilies will do well in almost any situation or garden setting, some can be touchier than others or require more care. This is certainly not to degrade or criticize more difficult types, but simply to help the newcomer to growing daylilies understand something of the variations that exist within the 70,000+ registered cultivars and the various species clones they might run across when shopping for plants to grow in their garden.

While many daylilies are offered in commerce, there is rarely any information offered as to the variations within those made available, as though all daylilies are a one-size-fits-all for care and performance. In this post I hope to make a general outline of some of the variations to look for when choosing daylilies for your needs.

To make this article effective, I will make some distinctions within the Hemerocallis by various attributes so that we can make some general guidelines for your use. To whit, species vs hybrid, spreading vs clumping, age of introduction, ploidy level, foliage type, flower size, scape height and flower complexity all play a role in the ease and potential uses for a given daylily in your garden. There are certainly other factors that can come into play, but these are good general categories to start with. For descriptions of specific cultivars, be sure to read through the descriptions here on this blog of the cultivars I offer. These descriptions of my anecdotal experiences with these cultivars will remain on the blog even if I stop offering one or more of them, in order to provide an informational resource to growers.

To start, it is important to understand that the majority of daylilies grown in cultivation in North American gardens are hybrids that derive from crossing the various species clones together. This was begun in the 1890's in England and was taken up by American horticulturalists with gusto in the early 1900's. A. B. Stout is considered the father of the hybrid daylily and did much of the early leg-work to lay the foundation for what we have today.

A good number of the species are still available today. The most well known is the dreaded 'ditch lily', Hemerocallis fulva var. 'Europa'. This vigorous running fulva clone is a triploid (triple chromosomes) that is ubiquitous and invasive. It is excellent for retaining banks, stopping soil erosion and can survive in almost any situation. It is escaped into vast areas of the continental US and is considered an invasive weed in many areas and is much despised by many, yet many of the traits we so value in the hybrid daylilies likely owe their origin to fulva 'Europa', as Stout made a concerted effort to use it in his early hybridizing work and it is ancestral to many hybrids. However, the early breeders made a concerted effort to breed the spreading habit out of the descendants of 'Europa' and so the vast majority of them so now running habit, instead being clump forming plants like the other species types in their ancestry.

The fulva clones make up one of the two main branches of daylily species - the 'orange' category (though some are more red and others pink). In addition to H. fulva 'Europa', there are other clones of the fulva species in cultivation, such as var. 'rosea'. var. 'Cypriani', var. 'Hankow', var. 'Korean', var. 'Chengtu' etc. These all spread from runners, but none have been shown to be as invasive as the ubiquitous ditch lily 'Europa'. All are excellent for large mass plantings, difficult areas and erosion control. While 'Europa' may be difficult in a garden, the others tend to be much better behaved and can make attractive garden planting, being hardy, adaptable and resilient over the majority of North America.

The second categories are the yellow species and their clones, such as H. dumortierii, H. citrina, H. multiflora, H. minor, H. vespertina, H. altissima, etc. They tend toward small flowers of gold to yellow color. The scapes can vary from short and top-branched to tall and heavily branched with many flowers. The flowers tend to be trumpet shaped and have a wildflower look that is charming in the garden. Foliage types and quality varies from species to species, but several are attractive, especially H. citrina and H. vespertina. For more on the species, click here. Many of the yellow species make a nice addition to the garden and are easy to grow.

The hybrids descend from crossing the species in various ways and then interbreeding those interspecies hybrids, selecting for desirable traits such as interesting flower traits and better garden performance. Due to this selection, many cultivars may have more garden value than the species, even amongst the oldest cultivars, because undesirable traits such as the trumpet shaped flowers, night blooming flowers or spreading root runners that can become invasive have been selected out of the garden hybrids. Also, traits such as interesting color combinations, outward facing and more flat-opening flowers, more rounded or more extremely elongated petals on the flowers can often be found in hybrids, even the older ones. None of this means the species don't have garden value though, and there are undoubtedly settings where one of the species or another would be very desirable.

As a generalization, many of the older hybrid cultivars are very durable, but this is not to be taken as a fact for them all. While some of the more modern hybrids are more delicate and demand more care, some of them are also very hardy and durable. However, with the older cultivars, there is more of a 'track-record' in regards to how they have performed over the years in many gardens and in many climates and environments. Time will prove the durability and survivability of new cultivars, but it is best for the average gardener to work with tried-and-true cultivars to be sure they are purchasing plants that fit their needs. The same may also apply at the beginning of a breeding program. However, for collectors, advanced breeders or specialists, this information won't necessarily apply and while they may grow and breed from some of the older cultivars, they will often be focused on the newest and most extreme things. These people will usually know how to deal with touchier plants though, should something new and very desirable prove to be difficult.

There are two main ploidy levels (number of chromosome sets) found in daylilies: diploid (two sets) and tetraploids (four sets). There are other ploidy levels, but the vast majority of cultivars will be 'dips' or 'tets'.  Most of the species are diploids (with some of the fulva clones being triploids) and most of the older cultivars are also diploids. The tetraploids were made by converting diploid plants to tetraploid (chromosome doubling) through the use of mutagens (usually colchicine). The tetraploids have been around since at least the 50's, but really didn't get going until later. By the 80's there were beginning to be a good few of them, and now they are more popular, with more tetraploids being introduced than diploids. I like both types and work with both, though I am a bit more focused on tetraploids.

The diploids are typically more gracile than the tetraploids, which are more robust, typically have thicker scapes, thicker petals and larger plants. However, things are not always so cut-and-dry, and there are exceptions to every rule. The oldest cultivars, well up into the 1970's will be almost exclusively diploid. The tetraploids of the 1980's, 1990's and early 2000's are well-known, tested in many gardens. Talk to people, read about their experiences with various cultivars. Find out what is working for a good many people and that may well be a reliable plant for your garden, though gardens and environments vary. Always be aware that what works in one garden may not work in yours, as conditions may vary just enough to cause a difference in performance. Some plants also perform better in warm climates, while some do better in climates with cold winters.

This brings us to foliage types. There are three registry categories of foliage type - dormant, semi-evergreen and evergreen. These are not scientific classifications. While I am sure every hybridizer makes every effort to register their introductions accurately based upon the plant's performance in their garden, the truth is that foliage performance is more of a continuous range of variation and really doesn't fit nicely into three discrete categories. 

There are extreme ends of that continuous range that seem are quite noticeable and distinguishable in most gardens. The term I prefer for the 'dormant' end is senescent, which means that the leaves all die off in the winter and the plant is either not visible above ground or only a small amount remains as a visible bud or tiny plantlet.  At the other end are those plants that do not stop growing and their leaves do not die off. Their leaves may be killed back due to winter conditions, but as soon as the nights are above 40 degrees or so, they will begin growing again. These could be considered evergreen, though that is perhaps not exactly accurate, scientifically speaking. The vast middle seems to be plants that fall in a variable range in-between these extremes. These might be registered as 'dormant', 'evergreen' or 'semi-evergreen'. They can be variable based upon the climate they are grown in. Ideally, semi-evergreen plants retain some of the plant above ground through the winter but are not in continuous growth. 

However, there can be considerable variation between the visual presentation of foliage type amongst many daylilies depending on the climate they are grown in. Some plants that "go dormant" in winter in a cold-climate garden may present as "semi-evergreen" in a warm-winter garden. Some semi-evergreen types in the south may have leaves senesce in the north. Some southern 'dormant' types aren't really fully senescent in the north. We see all these variations amongst the various species as well. 

You will often hear the generalization that "dormants are hardy in the north but not in the south and evergreens are hardy in the south but not in the north, with semi-evergreen types being hardy in both". This is of course a gross over-simplification, but there is a bit of truth in it. It is true that some evergreens are tender in the north and don't survive or at least fail to thrive without location in a microclimate or some heat/mulch/assistance through harsh winters. It is also true that some of the senescent ('dormant') types don't survive or at least fail to thrive in the south. 

However, it is not true for them all and such blank generalizations aren't really helpful. Each grower will have to experiment a bit to determine what thrives in their particular garden and and what level of care they wish to provide. Not everyone is going to want to spend the winter running about with frost-blankets. Not every grower is going to want to mulch twice each year. Not everyone is going to want to spend a lot of money for plants that don't then flourish and put on a show, but instead demand large inputs of time and effort. Some growers will just want to plant some daylilies and simply enjoy them, and that is fine. There are daylilies that will perform well under low-care, typical yard/garden situations. 

While collectors and breeders may be willing to apply extra effort to keep a special plant thriving, we can't expect that of the general gardening public - folks who may have busy lives that don't revolve around daylilies. There are many, many daylilies that can work in many garden situations. No matter what your garden design there is a daylily that will work. When I hear gardeners say they 'don't like daylilies', I always ask them questions about why. Time and again, they tell me about buying a daylily for a specific purpose that doesn't work out and it is almost always because they picked the wrong types of daylilies. Knowing both what your needs are and what daylilies will fit that need are essential in having a good experience.

Foliage type is often a very contentious issue within the daylily world. In general, most senescent (dormant - deciduous) types will do well in cold-winter gardens, while most semi-evergreen and evergreen types will do well in warm-winter gardens. This is not an absolute rule, as some of each type will flourish in most areas, but if you are concerned, start with the types that almost always do well in your area and then experiment with other foliage types, starting with those of other foliage types that do well in your area or that are known and noted by many growers to do well in climates similar to yours. From there, if you are happy with those and you 'get the daylily bug', you may begin to experiment with cultivars that you aren't certain of, because by that time you may be willing to take the risk, to apply the extra input and effort if you end up with something more difficult, or willing to let a difficult plant pass if it doesn't work out. At any rate, your experience with daylilies won't be soured from the get-go because you started with the wrong type(s) and observed a failure and possibly even the loss of a fair amount of money.

The final points I want to look at concern the flower and its uses and display in the garden. Flower size is a very important factor. Many modern cultivars show very large flowers. This is currently a popular trend in daylily breeder, but large flowers that wilt at the end of each day also can create a large sticky, wet mess draped across the remaining flower buds that will have to be cleaned off in order for the next flowers to open. Large flowers are beautiful and I have quite a few, but they take daily maintenance to not be a mess. If you do not have the time or inclination to pick off wasted flowers (called deadheading) each evening or first thing the next morning, then stay with smaller flowered cultivars. 

For most garden uses, smaller flowers may be preferable as they are often self-cleaning, with the flower of the previous day closing up and not draping over the remaining buds. I find that flowers of about 5" or smaller are best for average garden or homeowner use around the yard. These look clean and don't require a lot of extra care each day. 

Scape height is another consideration. Scape height can vary from as little as 8" all the way up to 6' tall. A short scape is lost behind tall plants, while a tall plant will not generally work in the front border. Plan your selections to work in the area of the garden you want them to grow by selecting wisely when it comes to scape height, but also be aware that scape height can vary on any given cultivar. Was it bred and grown in Florida? Then the scape may be shorter than the registered height in Ohio, and vice-versa. Late freezes can cause scapes to be shorter than average, as can drought conditions during scape formation. A newly planted division may not reach its full scape height its first or even its second year. Some daylilies settle in within the space of a year, but some take longer, up to two years or even three in some particularly finicky cultivars.

In addition to scape height, there is branching and bud count to consider. The more branches and buds a cultivar has the more grand the display in your garden will be and the longer it will last. A notable exception is cultivars that show a strong reblooming trait, such as Stella De Oro, Kanai Sensei or Substantial Returns, wherein several sets of scapes are produced in succession so you still get a long display even with few branches and buds.

I am often told by some gardeners that they find many modern daylilies garish and too loud in the landscape. While I don't agree (obviously) I do understand where they are coming from, but I then begin to explain to them that there are many types of daylilies other than the large flowered, overly ornate fancy types that are most often promoted today (and I do love those, by the way...) There are amazing cultivars with tall scapes with many branches and small flowers that can give an incredible spray of almost wildflower-like background color. There are short cultivars that have small flowers with wonderful use in the fronts of gardens, as borders or in pots on porches or balconies. Always remember that almost any combination of flower size and scape height you can imagine exists in the daylily world and with the versatility found within the hybrids and species of the genus Hemerocallis, there really is a daylily for every situation and every taste. Don't just buy what is currently popular. Take the time to find what will work for you.

In the next installment we will look at use of daylily color in the landscape. For use in the garden, self colored flowers are the most useful as background fill or for mass plantings. Bicolors and bitones can also make an attractive mass planting. Detailed or patterned types such as eye/edge, patterned eyes, edge no eye or those showing heavy ruffling, teeth, pie-crust or sculptural traits will often work best as specimen plants, loosing some of their specialness when en mass.

To read more about various types of daylilies for specific uses click here to read about Daylily Categories, or go directly to such topics as Breeding Uses, Garden Standouts, Interesting Flower Traits or Rust Resistance and Tolerance.