The Rocky Mountain Bonsai Society


The Rocky Mountain Bonsai Society (RMBS) is a plant society affiliated with the Denver Botanic Gardens. It was founded in 1975 with a lineage to the Denver Bonsai Club founded in 1945.   Please go to the website’s history tab for more information about the society’s unique past.

RMBS monthly meetings are typically on the first Tuesday of each month starting at 7:00 p.m. and held at the Denver Botanic Gardens’ Plant Society Building.  Non-Members are welcome at the monthly meetings.  Nine months of the year, members meet on the last Saturday of the month at various members’ homes / bonsai gardens.  Since 1973, on the Fathers’ Day weekend, RMBS has held a 3 day bonsai exhibition at the Denver Botanic Gardens to display some of its member’s best bonsai trees for the public’s enjoyment.

 * It is Rocky Mountain Bonsai Society's policy and practice not to collect native trees (Yamadori) without a permit from the U.S. Forest Service, The Bureau of Land Management or permission from a Land Owner.   

Constitution & By-Laws


Sorry, the weather on Monday and Tuesday caused us to cancel the regularly scheduled February meeting.  It has been rescheduled for Tuesday, February 9th.  Same topics, same place and same time.
February's Monthly Meeting/Program
Tuesday, February 9th | 7:00 - 9:00pm
Denver Botanic Gardens Plant Society Building
1007 York Street; Denver, CO  80206
Short Program - Colorado's Regional Horticulture Issues
with Hal Sasaki (Master Bonsai Artist and Honorary Life RMBS Member)
In the early fall of 2014, temperatures were as warm as 80 degrees, lulling the trees into a false sense of season.  Then on Nov. 10, the Front Range received a chilling shock when temperatures plummeted from 58 degrees at 8 a.m. to 16 degrees by 11 p.m., Temperatures stayed frigid for nearly a week, chilling trees and people alike to the core.  Of the 2.2 million trees in the city, Denver forester Rob Davis estimates that tens of thousands are dead from the November frost.
Colorado's weather is unlike any other region in the U.S..  Our friend, and master bonsai artist/teacher, Hal Sasaki, owner of Colorado Bonsai will speak with us about Colorado's Regional Horticulture, what species do well here and bonsai trees that need greenhouses to make it through the Colorado winter.
Main Program - Bonsai Soil
with Charlie Sisk (RMBS Member)
One of the most widely debated subjects for most bonsai enthusiasts is soil composition. There are a large number of soil ingredients that can be used when mixing your own soil; different mixes are used by different enthusiasts. Through the soil in the pot, the tree must be able to obtain water, nutrients and gases in order to grow. For this reason, a bonsai must be planted in a good quality bonsai soil.  There are a number of qualities that are required in a good soil mix; water-retention, drainage and aeration.
As we get ready for the repotting season, Senior Bonsai Member and Instructor, Charlie Sisk will help us select the right types of soils that work in Colorado and work with the various trees we have in our collections.
Public Is Welcomed to Attend - Please join us and there is no cost.
March's Monthly Meeting/Program
Tuesday, March 1st | 7:00 - 9:00pm
Denver Botanic Gardens Plant Society Building
1007 York Street; Denver, CO  80206

Short Program - Making a Root over Rock
with Patrick Allen (RMBS Member)
Main Program - Shohin Bonsai
with Les Siroky (RMBS Member)
***Community Outreach Event***
Echter's Garden Center
5150 Garrison St, Arvada, CO 80002
Spring Gardening ECHXPO
Fri, Mar 4th | 3:00 - 5:30pm
Sat, Mar 5th | 10:00am - 5:30pm
Sun, Mar 6th | 10:00am - 5:30pm
RMBS will have a booth at this historic Arvada nursery and will be doing 2 demos on how to make a bonsai tree.  Get ready to meet 100's of enthused Colorado gardners!
Saturday Study Group
Sat, Mar 19th  | 9:00am - 3:30pm
Repotting of Deciduous Bonsai Trees 
Workshop Lead - Darell Havener (RMBS Sr. Artist)
Denver Botanic Gardens
Bill Hosokawa Bonsai Pavilion
1007 York Street, Denver, CO  80206