What counts as an invasive tree species in Colorado?

Invasive trees are non-native trees that spread aggressively and cause ecological, economic, or safety impacts. In California, lists and inventories help identify which species are actively damaging natural areas and which are high-risk watch species.

Where can I verify whether a tree is considered invasive?

Start with California-focused inventories and plant profiles (such as Cal-IPC), then cross-check distribution in mapping tools and local extension or land management guidance.

Should I remove an invasive tree myself?

Small seedlings may be manageable, but many invasive trees resprout aggressively when cut. For larger trees, consult local guidance and consider a professional—especially near structures, waterways, or utility lines.

How do I report an invasive tree sighting in Colorado?

Use regional reporting and mapping tools when available and include photos plus a precise location. You can also contact local invasive species programs, land managers, or extension offices.

What is the biggest mistake when controlling invasive trees?

Removing the top growth without stopping resprouting or seed spread. Successful control usually combines correct timing, follow-up monitoring, and safe disposal to prevent re-establishment.

Colorado Invasive Tree Species: Identification, Reporting & Control Resources

Identify • Report • Control

Colorado Invasive Tree Species: A Local Companion to the Weed Trees Hub

This page is a Colorado companion to our national guide: Invasive Tree Species (Weed Trees). Use it to confirm what’s considered invasive in Colorado, verify identification, and find the most useful mapping and reporting tools.

Fast path: get photos → confirm ID → check inventories/maps → report → choose control + follow-up. The goal is to prevent spread (seeds and vegetative fragments) and avoid “cut-and-sprout” failures.

Jump to: quick links • Colorado hotspots • common invasive trees • verify & report • control playbook • FAQs

Colorado Quick Links (Start Here)

These are the fastest paths to “Is this invasive here?” and “Who should I tell?”

National hub

Invasive Tree Species (Weed Trees) — definitions, red flags, and prevention.

Colorado Noxious Weeds

Use the Colorado Department of Agriculture list for statewide priorities: Colorado Noxious Weed List.

Report a weed (Colorado)

Colorado’s “Report-a-Weed” guidance points to EDDMapS tools: Report a Weed.

EDDMapS Colorado

View lists + contacts and submit sightings: EDDMapS Colorado.

Tip: before you remove a tree, confirm ID. Some invasive trees look like natives or beneficial ornamentals. Incorrect removal is costly — and sometimes illegal if you mis-handle regulated plant material.

Colorado Hotspots: Where Invasive Trees Spread Fast

In Colorado, invasive woody species often gain a foothold where water, disturbance, and transport corridors overlap. Use this as a prioritization lens before you spend money cutting.

Riparian corridors Roadsides & rights-of-way Urban escapes Post-disturbance sites

Rivers & streams

Seed transport + moist soils = rapid establishment. Tamarisk and Russian olive are classic corridor invaders.

Windbreaks & old plantings

Legacy shelterbelts can become seed sources. Watch for spread into adjacent natural areas.

Construction edges

Disturbed soils create openings. Early detection is cheaper than mature-tree removal.

Trailheads & access points

High traffic increases introductions. Bag seed material and avoid hauling loose cuttings.

Practical strategy: start upstream (or up-corridor), remove seed sources first, then work downstream. Monitor for 2–3 seasons to catch resprouts and seedlings.

Commonly Tracked Invasive Trees in Colorado

Colorado’s lists and priorities vary by county, watershed, and habitat. Below are examples you’ll see frequently in inventories and mapping tools. Always confirm by location and program guidance.

Example	Why it’s a problem	Best next step
Russian olive (Elaeagnus angustifolia)	Invades riparian zones, forms dense stands, and alters habitat and stream function.	Check Colorado noxious weed guidance; prioritize seed sources along waterways.
Tamarisk / saltcedar (Tamarix spp.)	Spreads in river corridors and floodplains; can displace natives and increase management costs.	Coordinate in riparian areas and plan for follow-up treatments.
Tree-of-heaven (Ailanthus altissima)	Fast growth and aggressive resprouting; can spread from disturbed urban and roadside sites.	Confirm ID and use a treatment plan that prevents resprouting (don’t just cut).

For more species, start with the Colorado Noxious Weed List, then explore distribution and reporting options via EDDMapS Colorado.

Verify & Report: A Simple Colorado Workflow

The best reports include clear photos and a precise location. The best control plans include follow-up.

1) Photograph

Leaves, bark, flowers/fruit, full canopy. Note habitat and whether seedlings are present.

2) Confirm ID

Use trusted profiles and ID pages: Colorado Noxious Weeds.

3) Check presence

See lists, contacts, and mapping tools via EDDMapS Colorado.

4) Report

Submit sighting info through local programs or map/reporting tools (include photos + location).

5) Plan control

Match treatment to the species and site. Avoid spreading seeds or fragments during removal.

6) Follow up

Re-check for resprouts and seedlings. Most invasive trees require multiple visits.

High-risk sites: riparian areas, disturbed lots, road edges, and post-fire landscapes. If the tree is near water or within sensitive habitat, coordinate before you act.

Control Playbook: What Usually Works (and What Usually Fails)

Most invasive tree control fails for one reason: the tree comes back. Plan control around preventing resprouting and new seedlings.

Don’t “cut and walk away”

Many invasives resprout aggressively when cut. A one-time cut can create a thicket.

Dispose carefully

Seeds and fragments spread. Bag seed heads, avoid hauling loose material, and follow local rules.

Time it

Some treatments work best when the plant is moving resources to roots. Follow species guidance.

Want a national overview of invasive “weed trees” and prevention strategy? Go back to: Invasive Tree Species.

Colorado Invasive Trees FAQs

Where should I start if I’m not sure the tree is invasive?

Start with photos and a trusted profile. In Colorado, start with Colorado Department of Agriculture guidance, then confirm distribution and reporting pathways with EDDMapS.

Is every “non-native” tree invasive?

No. Many non-natives are not invasive. “Invasive” means it spreads and causes harm (or is likely to) in natural areas.

Do invasive trees always need herbicides?

Not always, but many invasive trees resprout after cutting. The safest, most effective approach depends on the species and site. Follow label directions and local guidance.

Colorado Invasive Tree Species

Softwoods

Hardwoods

Calculators

Resources

Programs