Wilding Your Garden

I recently gave a talk on habitat gardening titled, Wilding Your Garden. Yes I know that the very title is controversial since the word wilding has a rather unpleasant meaning in the urban context, but I kept it because it comes closest to conveying the message of the talk.

This fierce-looking insect, a robber fly, is an amazing predator that as an adult catches its prey "on the fly." It lays in wait on the leaf of a toyon in my garden. 

I knew that the gardeners attending this session were interested in learning about native plants that would be most effective in attracting birds, butterflies and hummingbirds to their gardens. My goal for the group, though, was to convince them that to attract these little pretties, they would need to change not only the plants they were growing but more importantly their approach to gardening. Although plants provide food for many critters, especially at certain times during their life cycle, most birds and many other animals need insect protein and fat for reproduction and to feed their young.

During the summer phoebe's swoop near the ground under the oak tree, catching insects in mid air.

If we are serious about attracting and protecting birds, butterflies and hummingbirds, we need to get serious about both native plants and insects. Furthermore, we must not only include specific plants in our gardens, but we must mimic our local natural environment. That means allowing some dead branches to remain on trees and shrubs, and letting twigs, leaf litter and other organic debris accumulate on the ground. It means allowing organic matter to decompose to be recycled back into the environment. It means banishing mowers, blowers, and chainsaws from the land.

The case for habitat gardening is most thoroughly and eloquently made by Douglas Tallamy in his watershed book, Bringing Nature Home. He points out that although many birds feed on berries and seeds, requiring high-energy food for migration or to make it through the winter season, most birds need fat and protein that comes from insects for reproduction and rearing their young.

We spent several months from spring through summer watching a hummingbird tend her nest and then feed her young. Even these birds need protein and fat for their young.

Similarly, although butterflies are attracted to a broad range of plants whose flowers provide high-energy nectar, caterpillars – the larval phase of the butterfly – often require a very specific host plant. The loss of butterfly species may not be due to a lack of appropriate nectar plants, but rather to the loss of specific larval host plants. In short, although plants with pretty berries, nutritious seeds and nectar-bearing flowers may feed birds and butterflies during a portion of their lives, many cannot survive without more specific host plants and an abundance of insects.

There was quite a ruckus beneath a shrub as this lizard did battle with a large beetle. The lizard whipped its head around beating the insect senseless and finally finishing it off. I did not get to see her dine, though. Can't imagine how she could consume something so large!

One can study individual birds and butterflies to determine specific needs, as good restoration ecologists must, but for the home gardener creating gardens using locally native plants that typically grow in association with each other is a most effective approach. Furthermore, removing or reducing lawn, and allowing our gardens to be a bit messy creates good habitat for a diversity of insects, lizards, and other critters necessary for the health of the birds and butterflies we so enjoy. Finally, this more naturalistic and holistic approach not only gives you a good excuse when your neighbor points out that your grass is not the greenist on the block, but it can increase your awareness and appreciation of the wild drama that plays out in the natural world of your garden.

For more resources, check out the last three slides of the Wilding Your Garden presentation and the list of links to lists of plants that attract birds (a mouthful!).

One day on my way out - and in a rush as well - I heard a sound right by the back gate. There I found this rather small spider wrapping up its prey. It took about five minutes for it to delicately wrap up its meal while swinging from its web. I stayed to watch, figuring that it was worth being a bit late. I can't remember now what I was in such a rush about but I will never forget watching this spider going about its important business.

Selecting and Planting Trees for Long Term Success

Children and adults are amazed by the upturned root of a large pine tree that blew over at Garfield Park during the storm.
The root seems quite shallow for such a large tree, possibly due to the frequent, shallow watering practices used in the park to maintain the grass.

Trees have been on everyone’s mind. Hundreds, maybe thousands, fell during the big windstorm on November 30th. People wondered whether the high failure rate was due, at least in part, to horticultural practices. Trees growing in parkways, receiving frequent, shallow irrigation, toppled over in the strong winds. Many of these trees had been subjected to root pruning during road and sidewalk repair. Surely these conditions resulted in much of the damage. Trees located next to houses and other buildings were watered on schedules better suited to the turf grass growing beneath them. In compliance with city regulations, many of these specimens received water several times each week for fifteen minute periods. The grass was green, but the trees grew shallow roots unable to withstand the nearly one hundred mile per hour winds.

It is possible, even likely, that under better conditions, fewer trees would have failed. In the next few posts, I will describe the ideal conditions for growing a beautiful, strong, long-lived tree beginning with selecting and planting new trees, moving on to caring for and training young trees, and finally, proper care for mature trees. I will try to include photographs of common, less-than-ideal practices, featuring both my own mistakes and others that can be seen in nearly any neighborhood.

Good, strong landscape trees start from the very beginning, with proper selection and care. Selecting a young plant that will eventually turn into a healthy mature tree requires the following conditions.

The lower branches should be left on young
trees to feed the caliper of the trunk. After a few
years remove them using good pruning cuts.
Remove them before they are an inch in diameter
or if they pose a hazard. Clear the grass sur-
rounding tree, leaving at least a foot of clearance.
Check the gray plastic protector to make sure that
the crown is still protected and that it is not
moist or infested with insects. Once the grass
is cleared there should be less danger of damage
to the crown from weed wackers and mowers.

1. Only trees with excellent form, both above ground and below, will be planted.
2. These young specimens will started in the landscape either from seed (acorn, etc.), or at least transplanted when young, say no bigger than 15 gallon containers, with 5 gallon being a preferred size. The longer a tree is in a pot, the more time there is for root damage or stress to occur. Smaller trees often experience less transplant shock and usually catch up quickly with large, older specimens.
3. The roots will be well formed, spreading out symmetrically, with no roots circling within the pot. If there is a young tap root, it will not have been cut or damaged. Trees often fail years after planting because they developed circling roots while still in relatively small nursery pots. These roots continue to grow in tight balls that never adequately anchor the trees, and eventually choke off water. They may fall in windstorms, or decline due to inadequate uptake of water and soil nutrients.
4. The young “nurse branches” will have been left intact to feed the main stem resulting in a well-developed trunk with a nice flare at the base, as the tree matures.
5. The new plant will show no sign of stress or disease.
6. Only trees adapted to the local conditions – climate, soil type, water, exposure – will be selected.

In our ideal world, this perfect specimen will be planted in an ideal location.

These sweetgum trees were planted beneath power lines and need frequent pruning by So Cal Edison resulting in unappealing trees with weakly attached branches.

1. It will be the right sized plant for its location so it will never be topped because there are power lines above, because it is “too big for the house,” or for any other reason.
2. Its roots will have room to grow and spread.
3. If irrigation is required, the tree will be watered according to its needs rather than the needs of nearby turf grass or tropical flowers. In general, it will be watered infrequently, usually once or twice a month when there is no rain, and deeply, soaking the soil to a depth of two feet or more for mature trees (p.84, CA Master Gardener Handbook).

Not only will our trees be perfect specimens when starting out, not only will they be placed in the ideal location, but also they will be planted in the way that gives them the best possible start.

Crown of tree (place where stem starts
to flare out to roots) is buried - this
tree does not have a chance unless
this is corrected.

1. The plant will be placed in a hole no deeper than the distance from the pot bottom to the crown of the plant. Ideally, the crown of the plant will be slightly above ground level when planted so the crown remains above the surface even if the soil compresses slightly.  A very common cause of failure for newly installed trees is buried crowns. The trees may be planted too deeply, the soil on which they stand may compress, or soil may be piled up around the tree much later. When I see a dead tree, I always dig down to determine where the base of the tree is – that is, where the trunk flares out to form roots. This area, the crown, must never be covered with soil.
2. The hole should be wider than the container that the tree was taken from. The walls of the hole may be roughened to make it easier for roots to penetrate the surrounding soil.
3. No amendments will be added to the soil. The native soil will be placed back into the hole.
4. The soil will be tamped down firmly so there is good contact between soil and roots, but not packed down so hard that the roots are deprived of water and air.
5. A water basin may be created around the plant to direct water to the root area. This basin will be checked periodically and removed if rains or irrigation leave the tree standing in a puddle. If this occurs, either irrigation will be modified so that water can penetrate the soil, or in the case of heavy rains, the berm will be removed.
6. Since a perfect specimen was selected, the young tree is unlikely to need staking. If there is a nursery stake, this will be removed during planting and the hole filled in. If staking is required due to other conditions, such as high winds or heavy public use, two stakes at the correct height, with flexible webbing will be used. The stakes will allow the plant to move so it can develop a strong root system, and an adequate trunk caliper and taper, with a good flare at the crown. Stakes will be checked frequently to ensure that there is no damage to the trunk and to confirm that they are still supporting the tree properly. They will be removed as soon as possible, preferably during the first or second year of growth.
7. The new specimen will be watered in carefully so that the soil is wet but not sodden. The water should soak into the root ball and the surrounding soil.  Water will be applied again after the first application soaks in.
8. Organic mulch can be used to moderate soil temperature and reduce water loss, though the crown area will be kept clean of soil and mulch.

Trees selected and planted this way are given an excellent start.  In the next few years they require careful attention to make sure their roots leave the planting hole, penetrating the surrounding soil. The following tips will help the new plant during this period of establishment.

1. Before the first hot spell, feel around the root ball to check for large air pockets. These can form if the nursery soil had a lot of organic material that decomposed after planting. Gently, but firmly, press the soil to fill these holes. If you need to add soil, use the nearby garden soil.
2. Again, mulch can help these tender plants through hot weather, though it is critical that the crown remains clean.
3. The young trees should be watered regularly so that they do not dry out, but make sure that the soil in and around the root ball is not sodden. When soil is completely saturated there is no air available for the roots, and the soil can become compacted. Furthermore, disease-forming organisms thrive in hot, wet conditions, especially when there is little air present (anaerobic), resulting in root rot or other plant diseases. Water well, water thoroughly, and then do not water again until the soil begins to dry out. It is best to water before a young plant shows signs of drought stress.

Young trees often require pruning to develop into well-structured mature specimens. In the next post, I will describe pruning practices that can prevent future problems. These include removing suckers and crossed branches, selecting scaffolding limbs, and protecting and encouraging the growth of a strong and straight lead branch.

Resources:
Iowa State University, Forestry Extension

Tips for Proper Planting of Containerized Trees
To Stake or Not to Stake

International Society of Arboriculture (Trees are Good website)

Tree Selection
High Quality Trees

USDA Forest Service

Tree Owner's Manual

University of California

ANR (Agriculture and Natural Resource), Lawn and Garden Catalog

Cooperative Extension, Center for Landscape and Urban Horticulture, Planting

Cooperative Extension, Master Gardener Program, The California Garden Web, Landscape Trees

California Master Gardener Handbook, Dennis R. Pittenger, Ed. 2002. Berkeley, UC California.

Planting and Care of Landscape Trees, Part 1, Pam Bone (90 min. video)

Planting and Care of Landscape Trees, Part 2,  Pam Bone (90 min. video)

Urban Forest Ecosystems Institute

Resources

Wildsuburbia

Trees or Grass

Cleaning Up After the Storm

The Wind Event

Save Our Trees

What I Learned About Oaks

I'm Not an Arborist...

Cleaning up after the storm

For the past three weeks, ever since The Big Blow (windstorm on night of November 30/December 1), I have received a multitude of offers to haul away the broken tree limbs from the front yard "for a very reasonable price."  I declined them all, waiting for Jim Walker, his son Todd, and the hard working crew of Western Arborists to come to remove the dead limbs dangling in the avocado and deodar in the front yard. The debris was to be chipped, and the limbs cut into 18-24 inch segments. All material was to be left on site.

Two men climbed the deodar early in the morning, while one assisted from the ground. Although they took proper safety precautions I watched nervously as they used chain saws to cut large limbs tangled through out the tall, old tree.

Each limb was roped before being cut. After the chainsaw made its way through the limbs, they swung on the ropes and were lowered safely. It was amazing to watch.

Arrows point out two men working in tree.

For scale, notice yellow hard hat of workman on ground. Those guys were very, very high up.

After the men finished working on the deodar, they started on the avocado. This old tree had a lot of rot in it. When I saw the damage after the storm I thought it might have to be removed. We are going to see how it does and as it starts to grow new branches and fill in a bit, I will have some of the very tall limbs shortened. Avocados are not like many other trees, their structure can get quite messy since they are so brittle and large limbs frequently crack. Although the deodar is taller, the avocado is probably more dangerous to work in due to the instability of the limbs.

Arrows point out two men in the avocado tree.

You can see how extensive the damage to the avocado is.

The limbs that had fallen and those removed from the trees were then cut up and stacked beneath the trees. Branches and other debris were chipped and deposited beneath the avocado.

Chips being deposited beneath the avocado.

Chips being piled against the trunk of the avocado.

Clean up is mostly done.

My work began once the crew from Western Arborist was finished. A pile of mulch sitting on the root system and against the crown of a tree can spell trouble. In fact, I saw a young oak, about fifteen years old, die from just this cause. A pile of woodchips was left near the base of the tree. In a very short period of time the chips started to decompose and the pile got very hot. The roots were probably killed by the heat and the lack of oxygen.

This lovely oak died abruptly after it was heavily pruned and the chips were left in a pile against the trunk of the tree. I did not have the heart to photograph it afterwards. (June 2004)

Notice the knot right above the chips.

I removed most of the mulch the very next day and continued spreading it - directly on top of the lawn - so that it is no thicker than about 6 inches anywhere on the roots.

The excess mulch was piled on the walk next to the house. Now that it is off the tree, moving it to a better location is less urgent.

I have spent a few hours each day since last week spreading mulch and figuring out how to use the logs and branches that were too large to chip. Yet another section of the lawn, approximately 400 square feet, is history. More pictures to come!