What is an Arboretum?

An Arboretum is an area devoted to specimen plantings of trees and shrubs. Distinct from a forest, nursery or park, it is in a sense an outdoor museum of trees. It is a place where many varieties of trees are grown for research, educational, and ornamental purposes; where trees and shrubs are cultivated for exhibition.

Why should we have arboreta and botanic gardens?

There are several reasons for a community to support an arboretum. One reason is that as more people take an interest and enjoy caring for their own home environment, it is valuable to have a place where they can see and compare mature plants and to study the different varieties that they may wish to include around their own homes.

Another important role the arboretum plays is in the area of conservation and preservation. Just as zoos have played a vital role in educating people about animals and their habitats and preserving endangered species, arboretums are places where endangered plants and trees can be protected and propagated to preserve the biological diversity of our planet.

A third vital role an arboretum plays in the community is providing an aesthetically pleasing place for people to visit and enjoy. “Green space” is important for not only the physical health of people but also for the spiritual and emotional health of individuals who want to feel in touch with their environment.

How is Klehm Arboretum & Botanic Garden unique?

Visitors will see at Klehm Arboretum & Botanic Garden a wide variety of trees and plants unlike anywhere else in the world. The Taylor brothers operated the Rockford Nursery on this site and had a strong interest to diversity. They introduced plants from all over the world. If this was just a naturally occurring midwestern forest, you might find 50 woody plant species; Klehm Arboretum has over 300.

How to Read a Klehm Tree Label:

Walk the Interpretive Tour

The terms “evergreen,” “semi-evergreen,” and “dormant” are often misinterpreted as relating to the winter hardiness of a daylily. In fact, they do not relate to the winter hardiness at all. A given daylily may belong to any one of these classifications and be hardy or not in a given climatic zone.

These terms loosely characterize the behavior of daylilies during the winter months. Just as with trees, shrubs, and other perennials, “evergreens” retain their foliage color throughout the winter. “Dormant” is virtually synonymous with “deciduous” and applies to those daylilies whose foliage completely dies off for the winter. “Semi-evergreen” is a catch-all term that applies to those daylilies whose foliage in the winter can best be described as somewhere between evergreen and dormant; the foliage dies back, but not all the way; there is still some degree of green left in the leaves.

While one or the other of these three terms may have been used in the description of a particular daylily, the plant may not behave that way in your garden. For instance: a daylily that is evergreen in one climatic zone may go completely dormant in another and vice-versa. In other words, whether a daylily is evergreen, semi-evergreen, or dormant depends not only on the particular daylily cultivar, but also on the climatic zone in which it is being grown. Here in our gardens in Zone 5, we have a number of daylilies that, when purchased, were labeled “evergreen.” Looking across the daylily beds in mid-winter, I fail to see any one of them looking evergreen; at best they have a bit of green left in their leaves, much like a semi-evergreen.

Come spring, however, when the daylilies begin their new growth, it easy to tell the dormants on the one hand from the evergreens and semi-evergreens on the other. Because the foliage of the dormants will have died off completely during the winter, their new leaves emerge in unscathed condition. Since the leaves of the evergreens and semi-evergreens did not die off completely during the winter, they have been exposed to the freezing cold. Their new growth, therefore, has leaves that have been damaged to some extent or other, usually looking pale green-yellow at the tips or for several inches down the leaf.

The bottom line: It really doesn’t matter how the daylily is labeled with any one of these terms. The issue is winter hardiness. Maybe in warmer USDA climate zones, like 8 and 9+ this is an important issue because it will predict what the daylily will look like in the winter, but here in Zone 5, even the “evergreens” look pretty dead in the midst of winter!

Back to – Daylily Article Index

For Reference – Glossary of Daylily Term

“What is the difference between evergreen and dormant daylililes?”

Oh boy. If I had a dollar for every time I’ve heard that question…

There IS a difference between evergreen and dormant daylilies and it’s NOT just about the foliage. Depending on where you live, the type of daylily you choose may mean the difference between a successful bloom season– or one that isn’t.

Basically, evergreen daylilies grow foliage all year long. They still only flower during bloom season– you won’t get daylilies throughout the year– but, if you live in an area that doesn’t get freezing weather, they will probably keep their leaves all year. If you live in a colder area, evergreen daylilies will still grow but their foliage will be bitten back in the winter. If you’ve ever seen winter damaged daylily foliage, you know that doesn’t look too pretty.

When people tell us they live in Southern California and need a daylily that can look good and take the heat, this is the first one we suggest. Clear lemon yellow and simply gorgeous, ‘Lemon Vista’ is a top performer no matter where you live.

A dormant daylily is one that needs a respite from the blooming season. In other words, they like to take a winter nap. A dormant daylily planted in a zone without a cold period may look great for a year or two. After that, the constant growth and bloom cycle will eventually become too much for them. They will wear themselves out and stop blooming. You’ve heard the phrase “no rest for the weary?” That’s a very real conundrum for ill-placed perennials in zones without a dormant period.

Dormant daylilies, like ‘Cherry Cheeks’ pictured here, tend to disappear in the colder months and reemerge in spring.

So what does all that mean? If you want to find out what daylilies grow best in your area, here is the short-and-sweet version of what you need to know:

  • If you live in an area that doesn’t get a cold period in the winter (like a zone 9 or 10), you’ll want to stick with evergreen or semi-evergreen varieties (semi-evergreens are somewhere in between dormants and evergreens).
  • Everywhere else, you can grow all daylilies regardless of foliage type.

Pretty simple, huh? (but oh so important!)

Ken Oakes and I made a video that discusses this topic in a bit more detail. If you want to see it, visit our YouTube channel at Oakes Daylilies, or just click this to go straight to it.

And, hey! Thanks for reading!

Shrub Leaves

While it’s often easiest to identify a shrub when it is in flower or bearing fruit, that’s only the case for part of the year. A more reliable identifying characteristic is the shrub’s leaves. Leaves are either simple or compound. Simple leaves are not divided in any way, like an aspen leaf. Compound leaves are divided into leaflets or needles, like juniper or ivy.

The other main characteristic is whether the leaves are opposite or alternately placed on the stem or branch. Opposite leaves are attached in pairs opposite each other, while alternate leaves are attaching singly at alternating sides or in a spiral.

The final easy leaf identification guideline is to note the type of leaf. It may be broad, narrow, or needle. Shape is a better indicator than size, since individual shrubs can vary in leaf size. There are three basic leaf shapes, excluding those of conifers: lobed, smooth, and toothed. Lobed leaves have curvy or forked edges, such as oak leaves, while toothed leaves have many small teeth along the edges. Smooth leaves, naturally, have smooth edges.

Shrub Flowers & Fruits

Identifying shrubs is easy in the spring, when those that produce flowers do so. Color, shape, and scent of blossoms can tell you a lot about what kind of shrub it is. The time of spring in which it blooms is also important. Some are very early-blooming, while others don’t blossom till late spring. Consult a local cold hardiness zone map to find out when certain shrubs can be expected to bloom in your area.

Note the size of flowers; large and showy blooms can be distinguished from close cousins that produce only small flower clusters. Fruits have as many defining attributes as flowers do: observe whether the skin of berries or fruits is hard or soft, whether there is fuzz on the fruits, whether they have nuts or seeds, and their color, size and shape.

Shrub Twigs

In the winter, you may have no leaves, flowers or fruits to consult in your shrub identification. You can still tell where leaves were placed on twigs or stems, by examining the branches for leaf scars and buds. Some shrubs will have buds at the end of each twig, called a terminal bud, while others do not, only having axillary buds along the stem instead.

Examine the color and texture of stems, as well. Rough or smooth bark might eliminate a possible identification, as could whether the buds are gray or red. Thorns or hairs on shrub stems also vary widely and can help identify a plant. They can be small or large, narrow or hooked, opposite or alternate.

Want to learn more about identifying shrubs?

Check out these Web sites chosen by us for more information on the subject.

The University of Wisconsin at Green Bay provides a tree and shrub introduction.

The USDA Natural Resources Conservation Service has a PDF Trees and Shrubs Pocket Identification Guide.

The SAPS online identification guide aim to help you achieve success with plant material that you may encounter in your teaching and learning. These identification guides are suitable for using with a wide age range – from primary through to post-16 as well as adults.
The “Key for identification of British trees and shrubs” provides a route to the identification of 80 trees and shrubs, commonly found growing wild in Britain and Ireland. The key is based on the arrangement of leaves on a twig OR features of a winter twig without leaves. You are taken step by step through different stages, matching your specimen with simple line diagrams and with brief questions that give you choice to go to the next stage. Species descriptions are supported by a wealth of background information, photographs of living specimens and distribution maps. A full glossary gives explanations of the botanical terms used in the key.

Visit the Identifying British Trees and Shrubs website
You can find further useful help from the FSC (Field Studies Council) publications, including the AIDGAP series of identification guides. Mostly in the form of convenient fold out charts, with colour diagrams and supporting background information, these guides offer identification of lichens, grassland plants, salt marsh plants, plants common on sand dunes, plants common on moorlands and others.
For further information contact:
FSC Publications, Preston Montford, Montford Bridge, Shrewsbury SY4 1HW
Tel 01743 852140
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Website: www.field-studies-council.org

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