What is the difference between a pergola and an arbor? If you look up the words in an on-line dictionary you will find arbor defined as something like, “A shady resting place in a garden or park, often made of rustic work or lattice work on which plants, such as climbing shrubs or vines are grown” (The Free Dictionary by Farlex). A pergola is defined as, “An arbor or passageway of columns supporting a roof of trelliswork on which climbing plants are grown.”

Landscape design writers such as Gordon Hayward and Cynthia Cash define the strict usage of the work pergola to refer to a colonnade or passageway.  About.com quotes Cynthia Cash, ”The primary difference in an ‘arbor’ and a ‘pergola’ is that an arbor is a free-standing structure (also used to support vines), whereas a pergola is a long linear structure over a garden pathway.”

Judging from images pulled up using Google, common usage of the word pergola defines it as a “substantial” columned structure which can either be over a walkway or, more commonly, over a sitting and dining space adequate for a group of people. While this could also be called an arbor, the word arbor is generally reserved for smaller structures over gateways or individual benches. Both arbors and pergolas are used as a structure to support climbing plants.

No matter how you use the words, arbors and pergolas are important elements to define, soften and divide both small and large spaces. Arbor gates create a defined transition between “outside” the garden to the intimate interior. They also frame a view into the garden at this threshold. A pergola’d sitting area, either attached to the house or freestanding, creates a defined outdoor room as well as breaking up horizontal lines of fences and garages.

Shannon and I were driving to a client site yesterday via 42nd St. in south Minneapolis. WOW! The entire street is lined with crab apples - and, in this high season, is literally draped in pink and white flowers. I think our crab apples must rival the Japanese cherries in this glorious time. The flowering doesn’t last long so if you have time head down 42nd St. between Hiawatha and the river, or the east side of Lake Nokomis, or the MN Landscape Arboretum or the Japanese Garden at Normandale College.

Well, its official: spring has arrived. We were able to get a crew out on Thursday and two crews out on Friday starting on garden clean-ups. Its exciting to start a new season. We have a GREAT group of employees and, as always, great clients who provide us the opportunity to beautify their landscapes and gardens.

I thought the worst conifer burn I would see was when a client threw an old Christmas tree on her fire-pit last summer. But the amount of burn we are seeing on garden conifers this spring is rivaling that blaze. And it isn’t just yews, Alberta spruce and newly planted trees. We are seeing it on Scotch and Mugo pines and even on low growing junipers. One client has a beautiful arching stand of Juniper ‘Saybrook Gold’ that is probably 10 years old…. torched.

What can you do to protect your prize conifers? Well… do you want the short answer or the long answer? The short answer is that wrapping with burlap works. We just pulled burlap off a ‘Golden’ Black Spruce (Picea mariana ‘Golden’) and it looked fresh as can be (last year it had a lot of burn due to reflection off the adjacent building).

The long answer would question the importance of the winter landscape and what the conifer is accomplishing in the design of the space. Is it there for winter interest? Screening? Specimen or accent? How jarring is it to see a  tree mummy out your window? This is probably a personal judgment and depends on how the tree was wrapped.  One thing is for sure — the Minnesota climate is not very friendly to conifers.