Thursday, January 29, 2015

A Guest-Authored Post by Di DeCaire

Identifying Dormant Daylilies in the North

by 

Di DeCaire

(Copyright April 15, 2014)

*For this post, I am featuring a guest author, Di DeCaire, who has written a great article about a northern hybridizer's experiential view of foliage types. This article is an expanded version of a great post Di made to the Robin. I think it is very important to consider the experiences of actual gardeners. While each and every gardener may have slightly different experiences, even in very similar conditions and with very similar plants, many points of reference will be the same. One thing that stood out to me was how much Di's article mirrored the anecdotes I hear from many northern gardeners I have spoken with or corresponded with over the last few years. In fact, her experiences closely mirror my own experiences with the various foliage types, though some of her winter conditions vary from mine. For instance, she may have more snow cover in any given year and even though we are in what is technically the same climate zone, she is considerably further north, being in New York, while I am in Kentucky. I hope you enjoy this article as much as I have and I hope you will take it in the light that it is presented - an experiential account of a northern gardener's personal views about foliage types.*

Di's caption for this photo - "The Beauty of Dormant Seedlings".
The above picture is from Di's garden in mid-spring. However, most of the photos in this article were taken on the same day (April 14, 2014) in Kathy Kosel’s garden, located in Upstate New York, to demonstrate the many variations of emergence that occur at the same exact time.

Northerners become positively radiant when they talk about dormant daylilies. If you live in the south you might wonder why. What’s all the excitement about?

Many dormants are green and pristine with no ratty or browned foliage upon emergence. Besides being visually pleasing, their clean appearance engenders a sense of confidence in the way dormancy works. Dormant foliage is often an attractive deep green through this first phase of growth. Some dormant daylilies show bluish green foliage, and these are the most prized of all.

A dormant with blue-green foliage, April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

The phases that a dormant daylily goes through are emergence, foliage growth, scaping, blooming, pod set and dormancy. There is a shutdown in active growth when a daylily goes dormant, ensuring that the fibrous roots are able to economize their sugar supply until spring. No new growth will develop during the winter. This good timing helps them bloom to their fullest potential in northern climates.

Rising temperatures activate a growth hormone called gibberellin in early spring. Rapid cell division occurs in the meristem and is triggered by gibberellin. It’s helpful to understand what a meristem is and its role in relation to dormancy. The meristem of a daylily is a lateral section of cell tissue located just above the crown. It is responsible for the origination of all cell tissue, both above and below ground. A damaged meristem means a damaged plant. A dead meristem means a dead plant.

In autumn when all the foliage dies back to the ground, new buds for the next year’s growth called resting buds develop from the terminal meristem. They remain underground and usually cannot be seen. These resting buds are exceptionally tough and hardy. A chemical similar to anti-freeze helps defend them from frost damage so when the new fans start growing in spring they often have better resistance to late frost damage than more tender evergreens.

Snow is a superior insulator for daylilies in the north. The earth’s heat radiates upward and bounces back down from the snow cover rather than escaping into the atmosphere. Thus areas with heavy snow cover can see evergreen cultivars that survive better and perform better than they may do further south where there is cold weather, but little or no snow cover.

Proper planting of a daylily is crucial because if the crown is situated too low under the surface of the soil the meristem may suffocate, but if planted too high it may be exposed to frost damage over the winter months and into early spring as well, when late frosts occur. I try to plant the top of the crown about three quarters inch deep.

To correctly identify an emerging dormant daylily look for clean fans with no browned or straw colored tips on the new growth, though if there have been late frosts after growth has begun, even some dormants may show some browning on the leaf tips. With dormants the past year's foliage will have completely died off the previous fall and by springtime is lying on the ground in a very wizened state. It’s fun and easy to count the number of growing points at this stage.

The growing points of a dormant diploid emerging in spring,  April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

Some dormants are referred to as hard dormants because they shut down early and completely. Shortening day length in the fall may trigger hard dormancy but this theory is unproven. Other dormants appear to need a succession of freezing temperatures for growth to cease.

A hard dormant emerging in spring, April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

The concern about evergreen daylilies in northern climates has to do with their perpetual growth. They are not programmed by nature to stop growing during the winter months like dormants. When evergreens manage to resume growth during winter thaws, the existing foliage as well as any new growth freezes when temperatures drop again. This winter growth is a waste of the plant’s energy reserves, affecting its overall vitality. Flowering potential is often diminished.

The photos of emerging daylilies included in this article were all taken on the same day (April 14, 2014) in Kathy Kosel’s garden, located in Upstate New York, to demonstrate the many variations of emergence that occur at the same exact time. These daylilies were mulched and partially groomed just days before.

In my region evergreens are identified in the spring by their browned foliage and possibly mushy or curled over fans. They often appear disheveled. The fall and winter growth freezing and the next round of growth getting trapped in the dried up brown parts cause this. 

This picture shows an evergreen cultivar with brown, mushy, curled-over foliage on April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

When the browned debris is pulled off green leaves may spring forth, unfolding like an accordion. If another frost occurs this new growth is subject to damage once again, whereas some dormants, though not all show some level of resistance to spring frost damage.

An evergreen showing scrunched up, accordion-like foliage on April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York. This accordion-like foliage may be caused by evergreens attempting to grow during winter warm spells while trapped under the browned, dead foliage.

When evergreen fans freeze and brown all the way down to the ground it is cause for concern. One has to hope that the meristem has not been damaged. It can be surprising to revisit a dead looking clump and see full size, healthy fans arising a couple weeks later but it often happens. Conversely, there may be a few empty spots in the garden where evergreens with the same appearance were not so lucky.

An evergreen clump showing missing fans where the meristem of those fans has died during the winter. Such tender plants will often show suppressed performance and poor, or even no, flowering after such fan loss. This clump was photographed on April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

It’s almost worse for us northerners when only a portion of the plant dies off because it is generally just a matter of time before more trouble occurs, leaving us in a state of uncertainty. Rescue fans may emerge from the meristem in an awkward assemblage as a way of helping the plant survive. These fans are often too small and narrow to give rise to a productive scape.

An evergreen showing heavily browned foliage but no apparent missing fans, from April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

Evergreen clumps should be checked for symmetry. An empty spot is a sign that some portion of the plant may be dead. There are evergreens that are quite hardy. These usually have some brown foliage in the spring but display good symmetry. It’s possible that some dormant genes are mixed in and they may not be 100 % evergreen.

This is an example of an evergreen showing little damage and in relatively good shape, even after the hard winter of 2013/2014. It is to be pointed out that there are hardy evergreens. While some evergreens are tender, there are many that are hardy to very hardy in cold climates. They may not be as attractive in the spring as hard dormants, in northern gardens, but they live, do not decrease and perform at or near the normal performance seen in southern gardens. This photograph is from April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

Crossing dormant and evergreen daylilies has proven successful for me in some cases. These seedlings possess the best qualities of both worlds, the coveted southern flower traits blended with the desirable hardy foliage habit. These crosses often result in what are determined to be semi-evergreens.

A typical semi-evergreen, showing intermediate traits to both true evergreen foliage and true dormant foliage. Photographed on April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

To identify semi evergreens in the north look for clumps with foliage that have some degree of brown at the tips, not as far down as evergreens, and no mushy spots. There are a number of variations resulting from the perpetual blending of dormants and evergreens by hybridizers worldwide.

This picture shows a semi-evergreen that is closer to true evergreen foliage. The photograph is from April 14, 2014 in Kathy Kosel’s garden, located in Upstate New York.

Daylilies that are nearly dormant are sometimes classified as semi-evergreen because they are not completely green at the tips. The longer outer leaves surrounding the clean emerging growth in the center have some degree of browning. These types often possess the same deep green or blue tinged foliage as is seen in some dormants and are normally quite hardy. 

Some semi-evergreens are closer to evergreen. The leaves are of fairly equal height, though the tips are usually somewhat browned. These variations can have quite minor differences and this makes identification tricky. Seedlings that are very close to dormant with a negligible amount of brown on the outer leaves can be hard to classify. Semi evergreens that look almost like hardy evergreens are also tough to classify.

For the more difficult to assess semi-evergreens in my hybridizing beds I try to make note of them as being near dormant, near evergreen habit or falling in the middle. The seedlings are labeled when they emerge in April (it’s a small program so I can afford to fuss). This assessment is not totally accurate at this early stage but helps when hybridizing. I paint white labels purple or green. Purple is for dormant, green is for evergreen and the semi evergreens are left unlabeled.

To compare the often-worrisome experience of brooding over the more tender evergreens to feeling a Zen-like absence of worry about dormant daylilies while watching them emerge results in one outcome for northerners - the dormant daylilies win our affection and we often want to collect them and hybridize to produce more of them.
A photo showing the three foliage types. The bottom plant is a dormant, while the center plant is a semi-evergreen and the upper plant is an evergreen. Photo from Di's garden in mid-spring. You can clearly see the difference in the dormant and evergreen foliage, while the semi-evergreen is intermediate to the two, suggesting that so-called 'semi-evergreens' may be the result of both evergreen and dormant genes combined within one plant. The variations we see in the 'semi-evergreens' may well be due to the various levels of genes of either type and their modifiers.

*I wanted to say a few words here at the end of the article. I want to stress that this article is the actual, hands-on experience of a northern gardener. It is not presented as a scientific treatise, but as an account of the experiences of foliage habit that many northern daylily growers share. Now with that said, I want to stress that I do not for one minute believe there is anything wrong with southern hybridizers and growers focusing on evergreen cultivars. What else would they focus on? Many dormant cultivars do poorly or will not even live in the south. Conversely, I do not think that northern breeders and growers should feel bad for sharing their experiences of the evergreen and semi-evergreen cultivars that do poorly in their winters. These are simply matters of reality. I know that reality, when discussed, may impact the bottom line of some growers, but it is still reality.

Now with that said, how can we find middle ground? While I think that any grower should focus on what is best for their area, one way that both northern and southern growers can work together to benefit each other (and themselves and their customers) is to try out each other's cultivars and honestly evaluate their experiences. In that way, northern-hardy evergreen cultivars can be documented and southern-hardy dormants can be documented. By then sharing that information back and forth, and making it available to fellow hybridizers, beginners and customers alike, everyone can benefit. 

While I don't expect southern growers to focus on breeding northern hardy dormants, any more than I expect northern growers to focus on southern-bred evergreens, when examples of southern-hardy dormants and northern-hardy evergreens are found and documented, those cultivars can be incorporated into the opposite programs to bring in traits that can results in plants that can flourish in both climactic regions. That is the best of both worlds and can bring benefit to each group, rather than the sometimes acrimonious finger-pointing we sometimes see around the issue of foliage habit.

So let's focus on the wonderful and diverse daylilies that we all love. There are many daylily hybridizers, more than enough that we can each do whatever we want, breed however we want and focus on different niches, and this all benefits the daylily. It is the diversity of our plant that has brought so many people to it, both to grow and to hybridize, and that is a good thing.*