Horticultural Art Society of Colorado Springs

10/15/2026

More details about the trail closures near the HAS gardens!

Part of the Greenway Trail is closed for up to four weeks during bridge construction. Here’s the detour and what park users are saying.

10/09/2026

🚧 Trail closure alert! Starting Monday, Oct. 12, the Greenway Trail on the west side of Monument Creek in Monument Valley Park will close for up to four weeks as crews continue work on the historic Cache La Poudre/Mesa Road Bridge.

The trail on the east side of the creek will remain open, with a short pedestrian detour in place. Trail users can cross Monument Creek at the Uintah Street bridge or the pedestrian bridge near the south end of the park.

Thanks for your patience as we work to preserve this 90-year-old bridge and improve safety and access!
🔗 ColoradoSprings.gov/CacheLaPoudreBridge

10/09/2026

COMMUNITY ALERT!!
The Greenway Trail on the east side of the HAS Gardens, but on west side of the creek, will be closed starting Oct. 12th for 3 to 4 weeks.
Please spread the word!

10/06/2026

Something new has popped up in the HAS gardens!

10/04/2026

The El Paso County Sheriff’s Mounted Patrol came through Monument Valley last week and stopped by the HAS gardens!
https://epcsheriffsoffice.com/el-paso-county-sheriffs-office-mounted-unit-introduces-2026-equine-partners/

10/01/2026

Work on the Mesa St.Bridge will continue until late January at least!
That’s the word we get from the city of Colorado Springs.

09/29/2026

09/26/2026

Published in The Gazette, Saturday, September 26, 2026
Year Round Gardening - NoxiousThistles
Amalie Fellini, Colorado Master Gardener
Photo Credit: Debra Stinton Othitis, Colorado Master Gardener Emerita

With autumn arriving, most w**ds are starting to seed or go dormant for the colder months. Wind carries thousands of seeds to any spot of dirt or crack in the pavement. Thistles are some of the worst, primarily because removing them can be difficult. This can be accomplished, however, if done properly.

In Colorado, there are five varieties of thistle on the noxious w**d list:
• Bull thistle, Cirsium vulgare, is widespread. Each plant produces 4,000 seeds every year. To help with identification, bull thistles have spines along the top of their leaves with cotton-like hairs along the bottom of the leaves.
• Canada thistle, Cirsium arvense, is one of the most pervasive noxious w**ds in Colorado. It reproduces via seeds as well as rhizomes that form new plants. These thistles are 2-4 feet tall, have no spines on their stems, and flowers that grow in clusters.
• Musk thistle, Carduus nutans, thankfully only spreads via seeds. Unfortunately, with up to 20,000 seeds on each plant, it still has a foothold in most of the United States. Its flowers have a distinct disk-shaped flower head that tend to bow over.
• Plumeless thistle, Carduus acanthoides, can grow to over 5 feet tall and easily outcompetes native plants. Flowers range from purple to deep red and grow in groups of 2-5. It features leaf-like spines that grow upwards towards the flower.
• Scotch thistle, Onopodum acanthium x tauricum, is a very dense plant with up to 14,000 seeds that remain viable for 30 years. These plants can reach 12 feet in height and 2 feet in width, often forming unpassable barriers. They can be identified by their wide, spiny, wing-like leaves.

Colorado also has beneficial thistles that are native to the region. Unfortunately, native thistles are frequently identified incorrectly as an invasive species and wrongly exterminated. Therefore, experts do not recommend removal of thistles unless you are certain they are one of the above-listed noxious species.

Bull thistle, musk thistle, plumeless thistle, and scotch thistle can be removed through mechanical means such as hoeing and digging. These methods are especially effective when completed early in the plant’s growth. Mowing and/or removing the flower buds is not recommended as they can increase flower production in the plant. Do not leave any flower heads lying around as they can still produce and spread viable seeds.

Removal techniques for Canada thistle, however, are the opposite. Due to its ability to reproduce from root fragments, pulling, hoeing, or digging is not effective. Unlike the other thistles, mowing frequently can be effective, especially with the use of herbicides. Herbicides can also be used, and are recommended for larger populations.
Learn more about noxious w**d management at https://ag.colorado.gov/conservation/noxious-w**ds/

Submit gardening questions to [email protected] or call 719-520-7684. The in-person help desk is open Mondays, Wednesdays and Thursdays 9 a.m. to noon and 1-4 p.m. Visit elpaso.extension.colostate.edu and register for upcoming classes at epcextension.eventbrite.com.

09/22/2026

Here’s information about the Mesa St., Bridge. Please call the city with any questions. Click on the link below:

In Progress Contact Department: Public Works City Engineering 719-491-5642 [email protected] Traffic ImpactsBeginning April 6Construction activities will begin on April 6, 2026 with a well-marked trail detour on the east side of Monument Creek. For trail updates, click on the "Tra...

09/22/2026

First day of Fall in the HAS demo garden!🌻