Protect Your Trees, Please!

trees-1-cover-photo

We all love trees in our built landscapes, but the odds are against their survival if we don’t follow a few simple rules. Although I’m not a horticulturist or urban forester, I’ve worked with people in those professions in the past and learned a lot from them. I’ve also attended lectures and webinars by renowned arboriculture expert, James Urban, from which I’ve gained valuable knowledge.

I’ve seen countless examples of trees that are improperly sited, planted, and/or maintained, which oftentimes has shortened their life span. Below I’ve listed some guidelines for design, installation, and maintenance that will increase the chances of your new trees thriving to a venerable old age, and keep existing trees healthy as well.

New Trees:

  • Shade trees such as Maples and Oaks should be spaced at least 35 feet on center for healthy crown (canopy) development.
  • Do not specify tree grates or guards. These will girdle (i.e. strangle) trees when their trunks outgrow the size of the grate hole or guard diameter. Better alternatives around the base of the tree are mulched areas, groundcover plantings, pavers on sand setting beds, or porous rubber surfacing, which the tree trunk can push away as it grows.
  • Avoid specifying staking and guying, since the guys are frequently never removed, girdling and killing the tree as it grows. A tree cannot survive if its supply of water and nutrients is completely cut off. (This action occurs in the cambium layer, just beneath the bark.) Trees do not need stakes and guys unless they are planted in extremely windy sites or have abnormally small root balls in comparison to the size of their canopy. In these cases, make absolutely sure that the stakes and especially the guys are removed after the first growing season.
  • Tree roots generally extend at least to the edge of the zone beneath the canopy of the tree, and often beyond that. Don’t limit the root zone to such a small area that the tree becomes stunted. Plan for its future growth where possible.
  • When the budget allows, invest in modular subgrade cells and structural soils to prevent soil compaction where trees are sited in sidewalks, plazas, and other hard-surfaced areas. These allow roots to grow sufficiently beneath paved sites, resulting in much healthier trees than those planted without these systems.
  • The planting hole should be at least twice the diameter of the root ball.
  • If roots are pot-bound (encircling the root ball), they should be unwound and extended out from the root ball as much as possible when planting.
  • The root ball should be set on firm soil so it the ball does not settle. The trunk flare, or collar, needs to be at least 3 inches above surrounding grade.
  • After the root ball is set in the hole, the areas around the root ball should be backfilled with un-amended native soil. Tamp soil in place by hand. Water heavily before mulching, and fill with more native soil where it has settled. Do not place any soil over the root ball.
  • Mulch should be about 3 inches thick, but no mulch should be placed within 6 inches of the trunk.
  • Trees should be watered at least once a week during drought periods for the first two years after installation. This means thoroughly soaking the root ball by hand, and not relying on sprinklers!

Existing Trees:

  • On construction sites, keep construction equipment and any other heavy objects away from the root zones of existing trees. I advise specifying/installing temporary fencing around the root zones for this purpose. Compaction of soil around roots will kill a tree.
  • Do not specify any grading within root zones of existing trees (neither cut nor fill). Cutting will destroy roots; filling will suffocate them.
  • Do not trench though a tree’s root zone, for installation of utilities or any other purpose. As mentioned earlier, this zone often extends beyond the tree’s canopy edge. The small feeder roots near the surface of the soil are just as important to the tree as its larger roots are. Cutting through any roots will often shorten the life of the tree.

All Trees (Old and New):

  • Do not “volcano mulch” around trees (piling mulch high around the trunk). This can lead to rot and decay of the buried part of the trunk, and result in a tree’s death. As noted earlier, mulch should only be about 3” thick, and should not be placed within 6” of the trunk.
  • Keep a mulch or plant bed around trees that are in an open lawn situation, instead of allowing grass to grow to the trunk. Turf adjacent to trees can be an invitation for overzealous weed trimming around the trunk, which can cut through the bark, particularly of young trees. If these cuts completely encircle the tree, this can result in girdling, leading to the tree’s death.
  • If you’re going to hire someone to prune your trees, be sure to hire a certified arborist for this job, not just anyone with a chain saw. Improper pruning can compromise a tree’s health.
  • Do not encircle a tree’s trunk and branches with strings of holiday lights, unless you plan to remove the lights after the winter season or holiday. If the lights are left in place indefinitely, the tree will be girdled as it tries to grow.

trees-2-straps
Death by tree ties
 
trees-3-grates
Trees outgrowing their grates and guards
 
Photo credits:
Top photo of large tree – Stefan Wernli (obtained from Wikimedia Commons)
All other photos – Alice Webb

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Red Butte Garden

I like to post photos of warmer seasons while we’re in the depths of winter, to remind us that spring is not very far ahead. Here are a few scenes from a lovely botanical garden on the edge of Salt Lake City, Utah, which I visited last June.
 
Red Butte Garden 1
Allium and falling water
 
Red Butte Garden 2
Four Seasons garden
 
Red Butte Garden 3
Herb garden
 
Red Butte Garden 4
Fragrance garden
 
Red Butte Garden 5
A roof garden with a view
 
Photos by Alice Webb

A Garden for All the Senses

Wickham Park in Manchester, Connecticut, includes a variety of themed gardens, the newest of which is a ¾-acre sensory garden. It’s a lush and peaceful place, with distinct spaces devoted to each of the senses. These types of gardens are very beneficial for people of all ages and abilities, gently stimulating the senses and serving as an educational tool.

This garden has a large variety of plantings, and is fully wheelchair-accessible. Pergolas and gateways separate each of the spaces – I particularly like those that are covered in vines. Although I might have designed this garden somewhat differently (perhaps with other types of seating and sculptures), I’m glad I had the opportunity to visit it.
 
A - sight garden
The sight garden contains colorful plants and a few with interesting shapes.
 
B - sound garden
The sound garden includes running water, wind chimes, and plants with leaves that tend to rustle in the wind.
 
C - scent garden
Plants with scented foliage and flowers are featured in the smell garden.
 
D - taste garden
A variety of edible plants and plant parts can be found in the taste garden, including vegetables, fruits, and nuts.
 
E - touch garden
Entry to the touch garden – this space features plants with various textures.
 
F - touch garden
Fine and coarse textures in the touch garden
 
Photos by Alice Webb

An “Urban Glade” in Miami Beach

The Lincoln Road pedestrian mall in Miami Beach includes a relatively new addition: a block of water gardens that evoke Florida’s Everglades. The site was designed by the landscape architecture firm of Raymond Jungles, Inc., and construction was completed in 2010. The surfaces of the water gardens are raised above the surrounding pavement, and include many native plants such as Bald Cypress, Red Mangrove, and Pond Apple. The biomorphic shapes of the gardens and seats are juxtaposed with the bold linear pattern of the surrounding pavement, creating an interesting combination of urban and natural themes.
 
Lincoln Road Mall 1
The gardens include a variety of plants that thrive in or near water, with an emphasis on native vegetation.
 
Lincoln Road Mall 2
Islands in the water gardens – these ones include large Bald Cypress trees. I’m guessing that the surrounding water somehow infiltrates the soil in the islands from below.
 
Lincoln Road Mall 3
A “dry” garden with Live Oak trees
 
Lincoln Road Mall 4
The gardens are raised above the surrounding pavement – some more than others.
 
Lincoln Road Mall 5
Mosaic surfacing forms bold stripes in the pavement.
 
Lincoln Road Mall 6
Water flows over this pond edge into a drain for recirculation.
  
Photos by Alice Webb

Think Spring (and Summer)

This is the time of year (in New England, as least) that many of us are really longing for warmer weather, tired of shoveling snow and otherwise being secluded indoors. The following images (from my garden in spring and summer) should provide some welcome relief from the bleakness of winter:

Barren Strawberry
Barren Strawberry

Chives in bloom
Chives in Bloom

Cranesbills (True Geraniums)
Cranesbills (True Geraniums)

Crocus
Crocus

Fritillary butterfly on Boneset
Boneset with Fritillary Butterfly

Goat's Beard
Goat’s Beard with Hostas

Japanese Iris
Japanese Iris

Lace-cap Hydrangea
Lace-cap Hydrangea

New growth - variegated Andromeda
New Growth on Variegated Andromeda

Red Admiral on Enkianthus
Red Velvet Enkianthus with Red Admiral Butterfly

Variegated Solomon's Seal
Variegated Solomon’s Seal

Violets
Violets in the Lawn

Photos by Alice Webb

Portland Japanese Garden

In Portland, Oregon, there is a lovely 5.5-acre Japanese garden situated in a hilly area west of the city center, within Washington Park. It is considered one of the most authentic Japanese gardens outside of Japan. I visited this serene setting in May a couple of years ago, and would like to share some of my photos.

Portland Japanese Garden A

 

Portland Japanese Garden B

 

Portland Japanese Garden C

 

Portland Japanese Garden D

 

Portland Japanese Garden E

 

Portland Japanese Garden F

 

Portland Japanese Garden G

 

Portland Japanese Garden H

 

Portland Japanese Garden I

 

Portland Japanese Garden J

 

Portland Japanese Garden K

 

Portland Japanese Garden L

 

Photos by Alice Webb

Plants for all Seasons

After deciduous trees have shed their leaves in cold climates, the landscape need not be a boring and drab scene. There are a number of plants that display ornamental characteristics during the chillier months of the year, sporting colorful and interesting bark, stems, fruits, and seeds. Below are a few examples that should brighten your day!
 

A stunning display of Bloodtwig Dogwoods
 

Crabapple fruit against a backdrop of fallen Ginkgo leaves
 

Hydrangea seed heads add visual interest to the winter landscape.
 

The bark of this River Birch appears to glow in the sun.
 

Although ornamental grasses die back in winter, leaving their flower stems and foliage in place until spring adds color and texture to winter landscapes.
 

Brightly-colored Weeping Willow branches enhance a snowy park scene.
 
Photos by Alice Webb