Monday, December 21, 2009

Evergreens of the Winter Solstice

Evergreens are an important plant to the winter landscape as they provide us with lively (or should I say alive) foliage in this lowest lit, dormant season. It is no wonder why we use them as Christmas trees.

Two Scotch Pines (Pinus sylvestris) centered in this photograph are remnants of a former windbreak of Scotch Pines -- all the rest have died of pine wilt and have been removed. We planted small one-gallon sized Green Giant Arborvitaes (Thuja 'Green Giant') in between the pines and now they are 15 feet tall and spires of green.

Green Giant Arborvitae are a good choice of evergreens in our climate and currently have no major pest or disease issues.

Many evergreens do suffer in our climate and it is difficult to recommend a fail safe variety. The Limber Pine (Pinus flexilis) photographed here in the Perennial Garden is succumbing to dothostoma needle blight -- an affliction that has made us remove most of these trees from the garden.


The Vanderwolf's Pyramid cultivar of Limber Pine so far has been immune to the leaf blight. A healthy example near the Rock & Waterfall trolley stop shows dense, healthy needles.

Eastern White Pines (Pinus strobus) remain one of the best choices for large evergreen trees in our region. They do require good drainage and protection from salt spray off roads to perform their best. They grow huge over time and naturally open up to a very layered appearance when mature. They were once (along with tulip trees) the tallest trees in Eastern North America. The tallest were cut for the Royal Navy's ship masts.
The Japanese White Pine (Pinus parviflora) has also done quite well and remains a much smaller tree as it grows so slowly. This plant in the Perennial Garden will be 20 years old next season.

Blue Spruce (Picea pungens) is an area-wide favorite and also does well as long as it doesn't get too crowded with poor air circulation around it -- such conditions cause cytospora canker which kills the lower or shaded branches. The Blue Spruce depicted is the cultivar 'Foxtail' which is a fast growing, very blue needled variety.
Our "bluest" evergreen at Powell Gardens is still the Blue Ice Cypress (Cupressus glabra 'Blue Ice') but it is supposedly not fully hardy here. Our plant has flourished but we haven't had a hard winter in almost 2 decades now.
Eastern Redcedar (Juniperus virginiana) is our toughest evergreen and the only locally native one! This seedling redcedar came up in the old Scotch pine grove and we are letting it grow to become part of our new windbreak. Many people hate this plant because it is not green in the winter, we feel it is a great color that seems appropriate to our landscape. Something truly green in midwinter must be sick here! It is an alternate host to cedar apple rust that afflicts apples and crabapples but we simply plant rust-resistant apple varieties (there will always be thousands of wild redcedars around!). The native redcedar is a top wildlife friendly plant.
This Southern Magnolia (Magnolia grandiflora) is a local selection and remains one of our truly greenest plants in the winter. Again, we are waiting for a severe winter to truly test how hardy this tree is -- its parent tree in Independence, MO, did survive past severe winters in the late 1970s through the 1980s.

The long needles of the Loblolly Pine (Pinus taeda) also are quite green now but this evergreen is also at home in a more southern climate. This tree is a seedling from trees planted at Powell Gardens several decades ago by the Boy Scouts and appears to be quite hardy though the long needles make it susceptible to ice damage. I should have had a person in this picture for scale, the tree is nearly 20 feet tall.
This morning was the winter solstice so each day from now until the summer solstice in June will be a bit longer than the next. I am glad that half of the dark half of the year is now over! Take some solace in the beautiful evergreens in this season. We trial a wide variety at Powell Gardens and have a marvelous collection of mainly dwarf varieties north of the Visitor Center in our conifer garden.
All photographs taken by Alan Branhagen on the winter solstice at Powell Gardens.

3 comments:

John Brooks Pounders said...

Wow, very nice pictures! Do you mind if I include some of them on our blog at AnythingGreen.com? The ones of the Thuja Green Giants in particular. I've been looking for some Thujas in a natural setting and not in the typical landscape setting.

kyle said...

Hi there,
Where exactly is the parent southern magnolia tree located in Indepence, MO? Is it in a nice park area?

Thanks : )

Kansas City's botanical garden said...

Hi Kyle,
The tree is at a private residence.