Gardening at Altitude in Colorado: Mountain Garden Guide

title: "Gardening at Altitude in Colorado: Mountain Garden Guide"

Colorado gardening is altitude gardening. The state spans elevations from 3,500 feet in the eastern plains to over 14,000 feet at its highest peaks, and each elevation band imposes distinct constraints: shorter frost-free seasons, more intense UV radiation, larger temperature swings between day and night, lower atmospheric pressure, and frequently alkaline soils derived from limestone and shale parent material.

Per Colorado State University Extension, Colorado's mountain gardeners face challenges that flat-country gardeners do not encounter: a last frost date that can arrive in mid-June at 9,000 feet; soils with pH 7.0–8.5 that restrict uptake of iron, manganese, and phosphorus; and afternoon thunderstorms from July through September that can batter plants with hail or dump 2 inches of rain in 30 minutes.

Table of Contents

1. Altitude and Climate by Elevation Zone
2. Colorado Soil Challenges
3. Frost Dates and Growing Season
4. Best Perennials for Colorado Mountains
5. Annuals and Vegetables at Altitude
6. Plant Selection Table
7. Irrigation and Soil Management
8. Common Problems
9. Frequently Asked

—-