November 15, 2019 Newsletter

Plantline – Spring 2018


Liquidamber straciflua ‘Worplesdon’

After all the Acer rubrums have lost their florescent leaves for the year, one tree continues to exhibit its colorful fall glory deep into the first frost. Whether it’s a selected cultivar or straight seedling, Liquidambar is a sweet tree (pun intended). Liquidambar styraciflua, American Sweetgum, has always been one of this author’s favorites ever since Plant ID class at Oregon State University. Sweetgum, who could forget that common name? It brings me back to Saturday football games and foggy Thanksgiving breaks. It was usually during this break that the Sweetgums got moved up in front of the garden center occupied on each side by pumpkins, cornstalks and Christmas wreaths or garland. American Sweetgum is well known for its fall colors of yellow, purple and reds. During the summer months it was always an eye catcher due to its rough, corky bark and its sharp star shaped green leaves. The seedlings will vary in color and texture but that always adds a bit of surprise come October and November. If one is looking for a more consistent fall color or form, look toward the most popular selections. ‘Happidaze’ is known for its deep rich maroons. This one will need some space as it is similar in height to the straight species, around 80’+ tall and 40’ wide at full maturity.

Happidaze’ may not be the best pick for a sidewalk tree but it does have its place in large landscapes such as parks, green spaces or allées. If street trees or mid-size backyard trees are more what your application calls for, check out the more tame selections of ‘Moraine’ and ‘Worplesdon’. Both of these are a bit more cold hardy as well spanning to zones 4-9. Each has weathered temperature lows to -25 F. Proper pruning will diminish the chance of limb breakage due to an unforeseen ice event or snow load. ‘Moraine’ is very broad and oval with leaves turning brilliant burgundy-red and yellows. In the nursery row it is usually one of the fastest growing. ‘Worplesdon’ usually doesn’t exhibit as much “corkiness” as the others, it is much smoother in bark texture. Fall colors range from apricot orange to purple. Recently more popularity has gone to the uprights. There are a couple of variations of the columnars but our favorite is ‘Slender Silhouette’. Great for backyard kitty corner fence placement but yet has great stand alone appeal in the front yard with small accent shrubs planted around or under it. It takes little to no maintenance and when planted as a hedge like a Carpinus fastigiata, it’s outstanding at only 6-8’ wide! Liquidambar has many great attributes, some of the not so desirable side effects of Sweetgums is they tend to seed fairly heavily and their fruit can be hard on bare feet, so keep that in mind when choosing locations. Not all varieties seed, and depending on stress factors many fruit less or more. If you are looking for some diversity in species or have just noticed the beautiful fall colors late into the season, Liquidambar is a great shade tree to consider.


• At Planting = just prior to or soon after
• After Leafing = wait for bud break and new leaves to appear
• Summer = wait for significant shoot development (leafed out). Pruning past July 15 not recommended

Type of Pruning:
• Hard = reduce top and limbs significantly
• Medium = prune to balance and shape for future growth (includes topping)
• Light = remove broken limbs and tip branches lightly
• Top = remove terminal (whips)
• None = no pruning, wait for growth, then remove dead wood, possibly thin limbs

** Always remove broken or dead limbs
*** May want to modify pruning if going into P & P program


Over the years numerous discussions have been initiated by customers regarding the pruning of newly received bareroot trees. The questions usually focus on when and how much to prune. Before attempting to address this subject, some issues need to be qualified. These guidelines are for field plantings for caliper trees. Retail and Pot-in-Pot plantings for quicker turn may be handled differently. This discussion relates mainly to tops, roots should receive minimal pruning to remove irregular, long or broken roots and to clean up root tips with fresh clean cuts.

These guidelines are based on observations and experience at Carlton Plants and in customers fields by Carlton personnel over many decades. If your program is solid and yielding good results, fine. If you feel there is room for improvement trial some trees with a different approach and compare results to traditional practices.

The preceding table lists genus and species in alphabetical order. Varieties are not listed and it is acknowledged that there will be some differences to be observed when pruning. There are definitions to clarify the verbiage used in the table for timing and type of pruning.

Cashing in with bareroot nursery stock

There are many benefits to be realized when buying and selling bareroot nurserystock, whether it be in a garden center or potting up for resale on a wholesale level. However, there is a concern that arises from the fact that many retailers and wholesale nurseries will pot all of their bareroot stock immediately into plastic containers and and hold it until it is totally rooted in. This can delay much needed cash flow and the sale of some varieties for quite a few months after being potted. This article explores alternative strategies, for handling bareroot stock in order to generate cash flow much earlier in the season. I have seen these strategies work successfully for many nurseries in our industry.

These three strategies are discussed in the following order:

  1. Selling unpotted bareroot stock before it leafs out.
  2. Potting and selling stock in a transplantable fiber pot.
  3. Creating a transplantable burlapped ball in a plastic container.

The first strategy is to sell bareroot stock un-potted to the public before it leafs out. This is an old garden center strategy that predates the use of plastic containers. It works particularly well with smaller and easier items such as fruit trees and flowering shrubs. Following are some key points to make this successful.

  1. Advertise your sale and let the public know that for a limited time they can take advantage of purchasing freshly dug bareroot stock at a lower cost than later in the season after it has been potted up.
  2. This program requires a display area where the roots of the stock can be mulched into bins to protect against freezing or dehydration.
  3. At the point of sale, roots should be packed with moist mulch, bagged and tied for the customer to take home.
  4. Planting and handling instructions should also be given to the customer along with a verbal explanation.
  5. Once any variety begins to leaf out in the bins, it is time to end the bareroot sale of that item and get it potted up. Note: Focus this program on easy leafing varieties. Those that are known for their slower leaf break, such as oaks, hawthorns, kousa dogwoods, etc. should not be sold bareroot.
Portland Avenue Nursery – Tacoma, WA

The second strategy for creating early sales is to pot bareroot stock into fiber or pulp pot containers. The advantage is that the customer can plant the fiber container in the ground without disturbing or damaging newly developing roots. This tried and true strategy can be used with virtually any bareroot stock; shrubs included. The following are points to consider.

  1. Not all bareroot stock needs to be potted into fiber pots. For example, some retailers will pot only their roses and fruit trees or early flowering trees into fiber containers.
  2. The customer should be given planting and handling instructions. The key is to advise your customer to cut openings in the sides and bottom of the pot before planting. This will allow roots to grow out into the earth unimpeded and will speed up the decomposition of the pot.
  3. Fiber pots are available with a water resistant treated bottom. Regardless, it is best if the pots are maintained and displayed in a high and dry, well drained area to prevent premature degradation of
    the bottom. A graveled or paved area would be best.
  4. Another benefit of fiber pots is that they provide some insulation for protecting roots from overheating or freezing.

The third strategy is to create an artificial burlapped ball in a plastic container. This program works very well with all bareroot tree varieties. Steps involved are as follows:

  1. Partially fill the container with a layer of potting mix to the level at where you want the bottom of the ball to rest. Also, you want to insure that a watering reservoir is left above the ball and a couple of inches below the pot rim once done.
  2. Lay two crisscrossed lengths of tying twine down in the pot and out over the rim, sufficient length to tie your ball with.
  3. Line the pot with burlap, using a sizable piece, large enough to create a ball. Because the burlap only need to last for a short time, until the tree roots out to the inside of the container, untreated burlap works fine.
  4. One trick is to use a plastic spreader to keep the burlap pressed against the inside of the pot when backfilling with media. A plastic spreader can easily be created by cutting the bottom off one, same size pot, and cutting the side wall vertically from top to bottom.
  5. With the twine, burlap and spreader in place, backfill with your media. Once the mix has been tamped firm around the root system in the container, pull out the spreader. The burlap is then pulled tight up and around the base of the trunk and tied into a transplantable burlap ball, which remains in the container for a clean display.
  6. After trialing a few of these, the procedure can then be systemized into a simple rapid moving process.
  7. When sold early in the season the customer simply slips the burlap ball out of the container and plants it without disturbing the root system.
  8. Again, as with the first two stratagies, there are key points to keep in mind:
    Printed and verbal planting and handling instructions should be given to the customer.
    Once planted, the customer should untie and cut away the top of the burlap.