Thursday, January 6, 2011

Winter Landscape Surprises

The winter landscape at Powell Gardens embraces the spirit of the season with beautiful dried grasses, bare bones of deciduous shrubs and trees, an abundance of fruit and a diversity of evergreens in many shades beyond green. Some nifty smaller perennials and surprising seedlings have added to the wonder of the garden. I am always humbled that there is something new to see and learn on every one of my routine inspections of the gardens.

Winterberry Hollies (Ilex verticillata) outside the Visitor Center are still ablaze with fiery red berries. This is the cultivar 'Winter Red' which becomes a large shrub over time (>8 feet) and can even be pruned into a mini-tree as our Horticulturist Duane Hoover has done at the entrance to the Kauffman Memorial Garden.

Red Sprite Winterberry is a much more compact cultivar that seldom matures taller than 4-5 feet. Remember these beautiful berry-studded shrubs are female plants and require a pollinating male -- actually 'Winter Red' is a late bloomer and requires the male cultivar 'Southern Gentleman' to set fruit while 'Red Sprite' is an early bloomer and requires the male cultivar 'Jim Dandy' to set fruit. We have several other cultivars of winterberry holly planted near the Visitor Center and 'Scarlet O'Hara' and 'Maryland Beauty' are also very beautiful now.

Every fall and winter I photograph the 'Asian Beauty' Linden Viburnum (Viburnum dilatatum) and it did not disappoint this year again with a heavy crop of red berries to color the winter landscape.

Crabapples also color the winter landscape but are not as vivid red as the winterberry hollies or viburnums. They still add a very nice splash of color to the browns and grays that are the bones of the winter garden's plants. This is the Zumi Crabapple (Malus x zumi or sieboldii) on the Island Garden where 8 of these glorious small trees provide lots of food for wintering birds.

The textures and subtle shades of winter evergreens are much appreciated through the winter. Green Giant Arborvitae's (Thuja plicata hybrid)sprays of flattened foliage is a lovely olive green with hints of bronze and gold.

Chicagoland Green Boxwood (Buxus hybrid 'Glencoe') also has bronzy-gold highlights to its evergreen leaves. This hardy boxwood was selected in Chicago for its good hardiness and foliage color in winter.

This English Boxwood (Buxus sempervirens) donated to us by the late Andy Klapis has much more rich green winter foliage. English Boxwood is supposed to be marginally hardy here but this one from the long-time area nurseryman has always weathered our winters with beautiful dark green, shiny leaves. This shrub can actually become a small tree in milder climates -- a fun fact is that it is the heavy wood from which billiard balls were made from!
The remarkable chocolaty-purple winter leaves of Girard Fuchsia Azalea (Rhododendron Girard hybrid) offer a completely different color for the winter landscape that contrasts nicely with other greens. This azalea has vivid red-purple flowers in spring and is actually becoming one of my favorite of the evergreen azaleas. For the most part, the darker the flowers of the azalea, the darker its winter leaves are -- the light green-leaved azaleas in the garden now will all bloom white next spring.

The cute, fine Monkey Grass (Ophiopogon japonicus 'Sparkler') has jewel-like blue berries now. This is the first time I've seen this here. Is it an artifact of a summer with rainfall and humidity more like Louisiana? Our Propagator, Marie Frye has collected some of these fruits to grow and see if we get some interesting seedlings. Sparkler Monkey Grass is a very underutilized groundcover that has done very well in sheltered woodland areas of Powell Gardens. It is utilized abundantly in New Orleans as a never mow, evergreen groundcover around homes.

The beautiful winter leaves of Italian Arum (Arum italicum 'Pictum') are a fine addition to the winter landscape but with changing climate this plant appears to be becoming invasive at Powell Gardens. It used to never bloom here but now readily produces jack-in-the-pulpit-like spring flowers that produce wonderful wands of bright vermilion fruit in the fall. We are finding copious seedlings in the gardens now. Should we remove it before it becomes an invasive exotic?

This native sedge (Carex unknown species) near the beginning of the Byron Shutz Nature Trail is a contender as a wonderful groundcover to replace grass. It is shade tolerant, fine and evergreen, never needs mowing, water or fertilizer. We will be transplanting plugs into garden settings for trial and also sending some starts off to Missouri Botanical Garden's Shaw Nature Reserve for further testing where they have wonderful native groundcover trial beds and are even starting some new native turf trials! There are over 60 species of sedges in Missouri and very few of them have been tested for ornamental and turf purposes.

This cute tussock-type native (Carex unknown species) sedge only about 8" across also may have garden potential. It's evergreen, very fine and stays in a clump. A mass planting of these would be lovely in a garden! It's another native plant for trial in the gardens. Obviously I have some work to do identifying these sedges but their short bloom time in spring when you can key them out to species is when I am most busy!

I've found several seedlings of evergreen Southern Magnolia (Magnolia grandiflora) around the gardens this winter. We never observed this until recently. A quick review of the USDA's Forest Service Agriculture Handbook states: "Neither seed nor seedlings can withstand a light freeze for 48 hours, and this may account for the limited natural range of the tree." Obviously our plants have not read this. The original native range of this tree was the deep South below the "Fall Line" but it is now naturally spreading northward from plantings.

Sweetbay Magnolia (Magnolia virginiana) has also began to self-sow in various parts of the garden. This magnolia is native into Arkansas and Tennessee farther north than Southern Magnolia.
Consider your own walk through Powell Gardens and its Byron Shutz Nature Trail this winter. I'm sure you make some surprising discoveries of your own. You will certainly get some ideas on how to enhance your own yard and garden's winter landscape.

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