Produce a shrub from a cutting? You bet!
Human eye still vital to the process...
...except where the computer's camera can see quicker!
Ten years to get to market
They've proven themselves winners
We were invited to tour two wholesale nurseries in southwest Michigan that produce many of the plants sold in local retail nurseries. Both of these nurseries are involved in the development and propagation of new plants. They both work with plant propagators from around the world to produce the latest plants. Neither one sells directly to the consumer but to other nurseries that then grow the plants to larger sizes.
Walters Gardens specializes in perennials. They are one of the leading growers of perennials in the U. S. since 1946. They sell plants as plugs and bare root. It's an innovative and cutting edge company and you can visit their website at www.waltersgardens.com for more information.
Whenever we're at Walters Gardens we always visit the extensive display gardens. These gardens have many of the plants Walters produces growing in garden conditions, very different from those in the greenhouse or in their growing fields. These display gardens are open to the public. If you're in the Zeeland area of southwest Michigan, we recommend a trip to Walters Gardens. All of the plants are labeled so you can note which plants you like and have the correct scientific name. There are some brand new plants, not yet on the market, so you can also see what's coming up in the near future.
There was a behind the scenes tour of the growing greenhouses. The size (500,000 square feet of greenhouses), organization and quality of the products are amazing. Learning how they produce plants is eye opening. These plants have to meet standards of uniform growth (makes it easier to package and ship), excellent root systems, and MUST be disease and pest free. The quality of the plants they sell is important to Walters Gardens and it shows. The greenhouses are clean and modern with the ability to control the temperature, humidity, amount of sun, and water.
Next we saw the area where tissue culture plants are placed in cells and flats to grow up. Walters Gardens was one of the first nurseries in the United States to have their own tissue culture lab. Many of the plants they sell are tissue cultured there. Some are grown for Walters in other labs around the world. They have quite a set up to get these plants from petri dish and gel media to a pot and growing media. The plants are all put into cells by hand which requires a gentle touch and knowledge of the plant to insure quality. Once in the flats they are placed in the greenhouses to grow on to sellable size. Some of these plants are eventually transplanted to one of Walters' fields so they will grow to a larger size for bare root sales.
The next stop on our tour was to one of the growing fields (farms, actually). Depending on the species, a plant may stay in the field for up to 2 years. Seeing the fields made me want to go in a hot air balloon just to photograph them from above. The lines are perfectly straight, thanks to GPS on the tractors and very colorful with flowers and foliage. Being outside in an uncontrollable environment means constantly monitoring the plants for insects and diseases. Walters Gardens has anywhere from 400 to 600 acres in production in any one year. The balance of their 1,500 acres is sown in cover crops to help improve the soil.
The other nursery we visited was Spring Meadow Nursery in Grand Haven, Michigan. This nursery specializes in propagation of shrubs and growing them to liner size. Those then go to other nurseries where they are grown on to the size we buy from retail nurseries.
Spring Meadow Nursery started in 1981 and has grown to be one of the largest providers of plant materials in the country. There are over 20 acres of greenhouses and 30 acres dedicated to stock plants. The tour was an eye opening experience in the production of woody plants.
The plants grown by Spring Meadow are mainly from cuttings taken from stock plants. The cuttings are taken at various times during the growing season, when the cuttings are most likely to root. They are then held in a cooled storage room and removed when they can be placed ("stuck") in flats. These flats are moved to greenhouses that are set up to provide the best environment for encouraging that particular type of cutting to produce roots.
All the cuttings are placed in flats manually in a production line process. Usually three workers work on one type of plant at a time. Each one of the trio places some cuttings in a flat as it moves past on a line. The last person fills out the flat and makes sure the cuttings are all in place.
Every one of those tubs contains thousands of cuttings -- thousands of shrubs!
The flats of cuttings are moved to specialized greenhouses, geared for encouraging rooting. These greenhouses have a computerized controlled environment that includes high pressure fog systems for keeping the humidity high, bottom heated floors to warm the growing media, and controls for air temperature and amount of sunlight. All these help create the best environment possible for encouraging cuttings to root.
Keep in mind that every one of those tiny plants is a shrub!
Once the cuttings have rooted they are moved on to other greenhouses that are controlled for plant overall growth rather than just root growth. These plants are constantly monitored for disease and insects, which are rare because of the controlled environment. However, the human touch is essential since it takes a knowledgeable eye to recognize if something does get into the area, and control it right away. In two of these greenhouses the floor is designed to be flooded if necessary so that plants can be watered from the bottom if they are susceptible to foliar diseases if the foliage gets wet. Roses are a prime example.
Tiny as they are, they must all be monitored daily for trouble. That scout in the photo can see even the earliest, most subtle signs of trouble.
These plants are now almost of the size Spring Meadows will ship to other growers.
The plants are not only monitored continually for pest problems but for root growth and uniformity of appearance and size. The more uniform the growth, the easier it is to package and send off to the nurseries that will grow them to sellable sizes for the consumer.
Many of the plants must be sheared to ensure uniformity. At one time this job was done manually by workers with hedge shears. Spring Meadow helped develop a machine that rides above the plants, fluffs them, shears their tops, brushes off the clippings and dumps them into the aisle for easy clean up.
There's the wonderful shearing machine. We sure wish we could have one for when we have those long, long hedges to clip... especially because it will clean up the clippings!
Quality of the product is what helped Spring Meadow grow and maintain a position as one of the largest growers in the U.S. Quality control has now moved into the computer age. Because all plants grow at different rates, even flats containing all the same type may include some poorer quality plants if not sorted. This was done by hand but is now done by a computerized grading machine.
Flats of plants are placed on a conveyor belt. They go through two stages that cut the flats so that each plant is now on its own. The individual cells are then routed to another conveyor that runs through a light box connected to a computer that grades each plant -- at 4 plants a second! The machine sorts the plants and places them in flats according to grade. Those flats go to shipping, back to greenhouses to continue growing, or are discarded and composted.
The last stop on our tour was where plants are evaluated for future production. It may take 10 years or more for a plant to be introduced and produced in enough quantity to go on the market. What we saw was just a part of the overall process: the plants are bred/hybridized and sent to various areas for trials. Some are selected for possible production and are trialed for a few more years. Sometimes plants perform differently than expected: they don't stay dwarf; they don't bloom as expected; they aren't consistent performers, etc. If a plant survives that final testing then it is put into production and introduced.