by Daphne Lewis, summer 2002
I harvest bamboo shoots from two Phyllostachys nigra var. henonis
groves located in Kirkland, Washington, USA, in the Pacific Northwest
Maritime Climate. Our climate is a dry summer/wet winter climate with
moderate temperatures year around. Our winter cold is the same as
Georgias which is USDA zone 8! Because we are so far north, we have
long days in summer. In June the sun sets after 9 pm. It rises in
the northeast and beams morning light on the north side of buildings
and bamboo groves. In the afternoon the sun sets in the northwest
and heats north facing walls. June is a glorious month where we enjoy
the gift of daylight for hours after coming home from work. In winter
we are dark at 4 pm; the sun rises in the south east and sets in the
southwest.
My two groves are the Driveway Grove and the North Grove. Both are narrow and run east and west.
The Driveway Grove is planted on the slope of the fill that forms the driveway parking area. Its leaves receive sun from the north, east, south and west. The soil is well drained since it is on a slope. It warms earlier than the soil of the North Grove because it is drier and because it receives sun all day long. The Driveway grove measures 750 square feet.
The North Grove is slow to warm up in spring. Its north side is shaded from the sun by six feet of fill on top of which is a two story house. It gets light only from the south. Its soil is dark and organic. Small drainage ditches go through which carry water much of the year. The North Grove measures 1200 square feet.
I do not own these two groves; I live 17 miles away, and have little free time to work them. The groves have never had summer irrigation. Until 1999 I did not mulch or fertilize the groves. Instead my work was to thin the culms in the Driveway Grove. I am still in the process of thinning the North Grove, although this year, 2002, it is mostly done except for a fringe bordering the neighbors house to the north. In 2000 I thinned approximately 3/4 of the North Grove.
1996 - First Harvest
In 1995 I began to thin the canes in the Driveway Grove in preparation for my planned first harvest in 1996. The groves remained congested, however, due to owner hesitation about change, lack of time on my part and the enormous volume of poles and leaves created by even minor thinning of an existing grove. In 1996 both groves yielded roughly equal pounds of shoots, presumably because each remained unthinned. After harvesting the shoots, I thinned the Driveway Grove some more, but not the North Grove.
1997 - Second Harvest
Thinning improved yield. While both groves increased productivity, the increase in pounds was greater for the Driveway Grove (partially thinned) than for the North Grove (unthinned). I was pleased to show the value of thinning an old grove to increase productivity.
1998 - Third Harvest
Both groves increased productivity over the previous years. None of the groves had received additional summer irrigation, mulch, or fertilizer. The Driveway Grove increased proportionately more than the North Grove. The only management difference was the fact that I finished thinning the Driveway Grove but the North Grove remained congested.
1999 - Fourth Harvest
Spring was so cold that harvest did not start until June 9. May mean temp was 52; Junes was 57 during days of harvest. My yields plummeted. I worried that I had starved the groves with three years of harvesting without adding mulch or fertilizer. The summer of 1999, I made progress on thinning the North Grove. Max and I spread lawn fertilizer and grass clippings. I expected yield to rebound in 2000 because of the addition of these nutrients.
2000 - Fifth Harvest
Another cold spring with a late start date for harvest. May mean temp was 50 and Junes was 57. The Driveway Grove yielded LESS than 1996 before I started managing it! The North Grove yielded about the same as 1996. In my search for an answer, I discovered that weather is a major factor in yield in the Pacific Northwest. In 2000 the average temperature in May was 54F. My soil thermometers show that the henon does not start shooting if the soil temperature is below 60F. Once shooting season is over, the warmer soil temperatures of summer do not induce shooting. The soil must be warm enough (60F) during normal shooting time.
2001 - Sixth Harvest
I put 4 meat thermometers in the groves, buried so just the dial showed. Generally no shoots came up if the soil temperature was below 60F (15C). The Driveway Grove heated to 62F (17C) on May 29 and produced 16.5 pounds. On that date the North Grove heated to 59F (14C) and yielded only 5 1/2 pounds along the sunny edge far from the shaded thermometers inside the grove. I found that during the shooting season, soil warmth is key. After shooting season the soil will warm above 60F (15C) but the shoots will not come. The starting date of harvest reflects the soil temperature and the soil temperature reflects the air temperature plus other factors such as drainage and exposure to sun.
2002 - Seventh Harvest
I expected 2002 to be the best year yet. Most of the thinning had been done in both groves. Fertilizer (25 pounds of lime, 40 pounds of 16-16-16, and 50 pounds of organic lawn fertilizer 6-3-2) had been spread in 2000 and the same fertilizer plus composted tree chips (about 3 yards) had been spread in 2001.
April and May were unusually cold. April felt like winter although the average temperature of 48.6F was only .6 degrees below normal. May was 2.3 cooler that average. It was the ninth coolest on record. In spite of the cold, yields were higher than 1996, 1999, and 2000. I believe there are several factors for reasonable yield in spite of cold weather and hence late harvest.
- Both groves were essentially fully thinnned by the preceding summer of 2001.
- Both groves had been fertilized for several years and mulched for two years.
- Both groves have fewer and larger culms than any other year.
The Power of Mulch
I spread about 3 yards of composted tree chips into the groves in the summer of 2001. This mulch was the grindings of mostly doug fir branches that had sat on the ground in the open for two years. They had been dumped by an arborist. I wheelbarrowed the chips to the edges of the groves and dumped it. I used a pitch fork to spread the chips into the grove. Some areas received mulch 6 inches deep; some areas received no mulch because the wheelbarrow did not fit between the culms. In 2002 larger shoots came up where I mulched. The unmulched areas grew smaller and fewer shoots and in one large area, none whatsoever.
The Variations within the Groves
Each grove has different parts that shoot at different times and produce different amounts. Areas that receive direct sun warm up earlier and produce better. In the Driveway Grove the steepest portion produces the least. Perhaps mulch and fertilizer and rainfall do not remain here. It is the coldest part of the Grove. In the North Grove the long South edge produces shoots. Behind it where the ground is low, wet, and shaded, this year there were no shoots at all. The east end of the North Grove has been thinned for a year now and sent up bigger and more shoots than any other spot in either grove. The ground is higher and drier here and I was able to wheelbarrow mulch there last year.
The Marketability of Fresh Bamboo Shoot
For the second year in a row, I sold my shoots to the Dahlia Lounge, an upscale restaurant in downtown Seattle. I charged them $2.50 a pound. I could have charged more but this is the price I quoted them last year.
The chefs were thrilled with the shoots. I enjoyed walking into the kitchen with my bucket of shoots because they fussed over the shoots. Mikal Czajkowki told me, When we cut these, it's so fragrant, it fills the whole kitchen! Yum! At first they used the shoots diced along with ginger, carrots, onions, and ginger to be filling for gyoza dumplings that they served with crispy rotisserie duck. Later they added bamboo to their menu explicitly: Pan seared Alaskan halibut, sugar pea broth, bamboo shoot stir fry, roasted oyster mushroooms and curry vinaigrette. $24. When I brought more than they could use, they sent it to their sister restaurant which made up their own recipes different from the Dahlia Lounge's.
How to Tell a Good Shoot from a Bad One
Wastage
Wastage tends to be 30%. As you get better at judging a good shoot, less wastage shows up at the cutting board. Small and/or old shoots are cut and left in the grove, instead. In farm situations these discards should be composted or fed to livestock. Left in the grove they could attract rodents. As my ability to discern good shoots from bad shoots improves, my percentage of wastage goes down. Also as my ability to cut the shoots out of the ground with less damage and more of the underground portion attached, wastage goes down.
Ideally a bamboo farm also has livestock, say chickens. All herbivores and most omnivores would rush to eat bamboo wastage. The keeper of the elephants at the Seattle Zoo said that bamboo shoots are like candy to elephants.
The Best Shoots are the Earliest Ones
The first thing I do when I arrive at the groves is take my flagging (surveyor) tape and go through the grove looking for the biggest and straightest shoots. If a big shoot is located where the grove needs a new cane, I tie the plastic tape around it. I only harvest shoots that do not have tape around them. When harvest season is over, I see the big healthy shoots marked with tape going up evenly scattered through the grove and I am glad I did not harvest them. I am convinced that the best shoots are the earliest ones. You dont get a second chance for a big replacement culm. Think of the future health of the grove when you decide which shoots to harvest and which to leave. I remove the tape after harvest.
Bamboo Grass
When you cut a shoot, some of its base usually remains. This base sends up miniature branches. These look like grass growing in the grove, bamboo grass. I believe that after shoots are harvested and after poles are cut, chickens and other fowl should be let loose in the grove to eat this grass. It looks better with ground weeds gone. Mites cluster on the leaves of the bamboo grass. It is easier to see emerging shoots and harvest them at their prime in a weedfree location. Animals love and thrive on bamboo leaves.
I don't have chickens so I use hedgeclippers. This year before cutting shoots I would cut the bamboo grass down. Later I noticed that some shoots had had their tips cut off. I realized it was I and my neatnik hedge cutters that had ruined so many shoots. Do not cut bamboo grass during shoot harvest season because new shoots tend to come up from the same rhizome as the grass.
Numbers of Poles Harvested
I find volunteers to help me thin the groves right after shoot harvest season is over. Usually there are people who want poles for pay or who are interested in bamboo and are willing to help for a day. This year my volunteers took home 150 poles. Most were 1 1/2 to 2 1/4 inches and most were 12 feet long. At $3 a pole (arbitrary figure) the poles are worth $450.
Culm Tops
For me the biggest problem in managing my groves is getting rid of the branched tops once the poles are cut off the unbranched bottoms. We cut 12 feet off the bottom where there are no branches. This leaves 18 or more feet of culms with branches and leaves. On a farm these can be fed to horses, cows, pigs, birds, and herbivores in general. In my case we loaded a truck with the tops and drove them to the Seattle Zoo. The keeper of the elephants said, The elephants eat about 6 poles a day. They eat the leaves, the twigs, the branches and the canes. The keepers of the orangutans like to stuff raisins into the canes. Gives the orangutans something to do.
One year we put the tops through a sileage machine. Bamboo tops seem to make good silage although that research was never written up.
It took two sessions to thin the groves. The truck to the Zoo broke down the first day. We piled the branches and tops to one side of the driveway and came back two weeks later to haul them to the dump. The leaves on top of the pile were brown and decaying after being rained on and hit by sun. At the bottom of the pile, the leaves were still fresh and green and able to be fed to animals.
When to Cut Poles
I cut poles about two weeks after shoot harvest is over. I look at each new shoot that is growing into a culm and remove from its vicinity at least one old culm. I look to be sure that each new shoot has ample space to shoot straight up and open its branches wide so its leaves receive sunlight. Sometimes I need to remove as many as 5 canes for each new shoot to have the space it needs.
The second reason for harvesting at this time is that the older culms have less starches right after shooting. Their stored starches have gone to the production of new culms. Although in our climate, pole eating insects seem not to exist, in other climates the quantity of stored starch influences the poles susceptibility to insect attack. The pole is of higher quality harvested at times of less starch.
