American Holly (Ilex opaca) is probably the toughest broadleaf evergreen tree for our climate. Here is one of our largest trees (20 feet tall; remember we are a young garden!) -- you can see it out the windows from the gallery/multipurpose room of the Visitor Center's north wing. It is studded with bright red berries and one of the best wildlife plants (for both winter cover and food).
American hollies are very strong wooded and weathered the catastrophic ice storm of 2002 well. They are almost impossible to find at nurseries: our specialty varieties have come from Fairweather Gardens, NJ http://www.fairweathergardens.com/ which is a superior source for mailorder plants and they are Powell Gardens supporters (one of the owners is from Omaha). This tree depicted was purchased from the only source of larger plants: Roberts American Hollies http://www.roberts-landscaping.com/ which field grows real American hollies in Kentucky. A reminder 'Greenleaf' hollies available at local nurseries are really hybrids and not nearly as hardy or sturdy but do grow fast (see earlier blog). American holly is found wild in the "bootheel" of Missouri so is promoted by the state's Grow Native! program so check out their website http://www.grownative.org/ for any other Missouri sources. American holly is a tree that grows slowly while small but is definitely worth the wait! Remember you need male nearby for female trees to set fruit.
'Christmas Snow' American holly is one of the few variegated cultivars. Its striking leaves have whitened edges. We grow ours near the wall because it is reportedly less hardy but has never had any problems for us in the past 8 years. Look for our small bushy plant on the south side of the Visitor Center Conservatory wall. American hollies can grow very bushy as a new plant then all of a sudden decide to send up a central leader and become a naturally pyramidal tree. Our plant is covered by self sowing castor beans in summer -- so is possibly why it has an irregular form.
Dwarf Golden Korean Fir (Abies koreana 'Aurea Nana') is a exquisite dwarf conifer that can be seen in our new dwarf conifer garden at the north edge of the Visitor Center. Our plant was donated by Marvin Snyder, past president of the American Conifer Society. The needles are golden yellow above and silvery beneath for a striking contrast. Always plant this conifer in well drained soil and protection from our hot afternoon sun and harsh summer winds. Ours has a bigger 'Acrocona' spruce protecting it and it did fine through last summer's harsh conditions.
'Callaway Large Leaf' Possumhaw Viburnum (Viburnum nudum) sometimes called Smooth Witherod Viburnum has been completely evergreen so far this year. Normally it looses its leaves by now but the exceedingly mild weather (despite more snow than in the past 20 years!) has allowed them to turn interesting shades of purple. It has some of its beautiful blue fruit but birds have devoured most of them. This plant was purchased from Fairweather Gardens and we are providing starts to a Nebraska based wholesaler. Look for our plant below the Conservatory on the east side of the Visitor Center.
Virginia Pine (Pinus virginiana) is a bushier pine that goes against our notion that all pines need to look like Christmas trees. It is the best pine for wildlife in the area because it produces large crops of cones every year. Many unique song birds relish the seeds and it provides dense cover for shelter on cold, windy winter nights. It is native as far north as Southern Indiana and Ohio and does really well in our climate and soils. Look for older plantings and naturalized seedlings and saplings along the latter part of our Byron Shutz Nature Trail. The tree depicted was a naturalized seedling we moved to south of the Rock and Waterfall trolley stop.
'Montgomery' Blue Spruce (Picea pungens) is a bushy growing Blue Spruce. If you don't have much garden space and love blue spruce, try this cultivar which is readily available at local nurseries. Look for this plant south of the Rock & Waterfall trolley stop.
Shocking Contrast! This 'Edith Bogue' Southern Magnolia (Magnolia grandiflora) is offset by some special, borer resistant selections of white-barked birch (trial plants from the North Central Experiment Station in Ames, IA). Both aesthetically striking with bright, shiny green leaves against the white trunks and ecologically shocking since birch are characteristic of northern climates and the magnolia from warm temperate southern climates. This magnolia was donated to us by Mike Shade of the Botany Shop in Joplin, MO http://www.botanyshop.com/. We have a great display of southern magnolias around the sheltered walls of the Visitor Center but we have planted some out on the grounds for trial in more harsh conditions. This plant has been defoliated by past severe cold but has not died back. The birches and other trees have now grown up around it giving it more shelter. This is a beautiful sight at the Rock & Waterfall trolley stop.
'Margarite' Southern Magnolia (Magnolia grandiflora) is a wonderful local selection of southern magnolia we made from a tree in Independence. It is named after its owner who let us have cuttings. It roots well from cuttings and a small second year plant can produce a huge white flower! Our biggest plant is by the visitor center (see prior blog) but depicted is a trial tree out at the Rock & Waterfall trolley stop to give a better test of hardiness. So far it has been our best cultivar on trial. Seed was shared with the Magnolia Society (international) and we were informed seedlings of the tree are now growing in England! We like this plant for its apple green leaf color, abundant bloom and pyramidal form. We have more cuttings rooting now and may offer it at a future plant sale (May 2009?).
Black Hills Spruce (Picea glauca 'Densata') is one of the best spruces for our climate. It is native to only the Black Hills of South Dakota so can take both extremes of hot and cold well! It has very fine short needles and abundant small cones. Look for this tree by the Rock & Waterfall trolley stop.
Serbian Spruce (Picea omorika) is another of the best spruces for our climate taking both heat and cold well. This plant was donated to us from Marvin Snyder and was originally labeled a dwarf ('Nana') but has begun to grow very fast become upright like a typical Serbian Spruce. We like it for its bluer new growth, strong pyramidal form and abundant tiny cones. Look for this plant at the Rock & Waterfall trolley stop.
Winter Honeysuckle (Lonicera fragrantissima) is a NON-INVASIVE honeysuckle that is tardily deciduous or semi-evergreen in our climate (so far evergreen this winter!) It makes a great large screen plant and its very fragrant flowers are some of the first to appear -- late January last year, then frozen off but always reblooms when spring arrives. It is a great source of early nectar for honeybees and will be planted in our new Heartland Harvest Garden's "honeybee haven" for just that reason. We often have people smell its deliciously lemon scented blooms and wonder where the smell comes from. These large shrubs are southeast of the Visitor Center just off the main "dogwood" walk.
Grape-holly (Mahonia japonica) is a marginally hardy evergreen with very striking winter leaves. It is mainly available at local nurseries as Mahonia 'Bealii' but Mahonia japonica is allegedly hardier. Recent mild winters have allowed these beautiful plants to thrive in our zone but any temperatures colder than -5F seem to damage this plant. (it can kill to the ground but usually returns from the roots) The big spider looking part at the center of the leaves are the flower buds which rarely open for us in February because they get frozen off by severe cold. Where fully hardy this candelabra of fragrant yellow flowers is spectacular. This grape-holly can be seen growing below the Visitor Center's Conservatory deck where it is especially protected. It is a great plant for such a space where something very shade tolerant is needed. Ours has never frozen back but it is growing in a very protected location.
All the photos were taken by Alan Branhagen on December 31, 2007 at Powell Gardens.