Read our Q & A postings answering common Colorado gardening questions here. Keith Funk is handling these this year. You can also hear him and fellow Wise Guy, Jim Borland, on the Garden Wise Radio Show on Legends 810AM, every Saturday morning from 7-9.

Special thanks to Kelly Grummons for thoughtfully answering these questions for many years.

Have gardening questions? Click here to send us your question on our contact form. Use our search window below to find Colorado gardening questions & topics.

3 days ago
1 min

Pine Trees Losing Needles?

Q: I’ve noticed my pine trees are losing yellow needles. Is this a symptom of a problem? A: Fall needle drop in conifers, where trees...

3 days ago
1 min

Should you aerate your lawn in the fall?

Q: It’s been a few years since I aerated my lawn. Is fall a good time? A: Fall lawn aeration is an important task for maintaining a...

3 days ago
1 min

Planting Trees in Fall

Q: I’ve noticed local nurseries have put their trees and shrubs and perennials on sale. Is it okay to plant this time of year? Fall...

3 days ago
1 min

Bringing Plants Inside for Winter

Q: I have a hibiscus, spider plant, coleus and several other tropical plants that have spent the summer outdoors. Do I need to do...

Jul 28
2 min

What to do about powdery mildew

Q: I’m seeing that white, powdery mildew developing on the leaves of my peonies, garden phlox, lilacs, roses, squash. Should they be...

Jul 27
2 min

How to check sprinkler output?

Q: How do I measure how much water my sprinklers are putting down each time I water? A: Unless you know how much water in inches you...

Jul 27
2 min

Q: How much should I be watering this time of year?

A: Watering effectively during the heat of summer can be tricky, especially with new plants. My first response is to water deeply and...

Jul 27
1 min

Colorado Fall Vegetable Garden

Q: What vegetables are good choices for a fall harvest and when should they be planted? A: Our average first frost date in Denver is...

Jul 6
1 min

Is it too late to plant now that it’s hot?

Q: Is it too late to plant now that it’s hot? A: Planting during the heat of summer is perfectly fine. It just takes some extra...

Jun 28
1 min

Should I remove flower heads from garlic?

Q: My garlic is sending up what look like flower spikes. Do I leave them or cut them off? A: Those are the flowering scapes of the...

Jun 28
1 min

What is eating circles in my rose leaves?

Q: Something is removing perfectly circular sections from the edges of my rose leaves. Is this a problem I need to treat for? Will it...

Jun 28
2 min

Pruning Dwarf Conifer Tree

Q: I planted what was supposed to be a dwarf conifer many years ago & it's now about 10' tall & so exuberant that's taken over the...

Jun 28
1 min

Will any verbascums rebloom if you cut off the dead flower stalks?

Q: Will any verbascums rebloom if you cut off the dead flower stalks? A: Yes. The smaller growing varieties of perennial verbascums...

Jun 28
1 min

Brown sunken spots on the bottoms of my tomatoes

Q: What is causing the brown sunken spots on the bottoms of my tomatoes? Is it a disease? Can I still eat them? A: What you are...

May 31
1 min

What to do with spring flowers after they bloom?

What should I do with my spring flowering perennials that are done blooming? They are looking a little messy. A: Remove spent flower...

May 31
1 min

Should I test my soil every year?

A: I purchased an inexpensive soil test kit from my local independent garden center to test my pH, Nitrogen, Phosphorus and Potassium...

May 31
1 min

How often should I feed the plants in my landscape?

A: If it’s been more than 3 or 4 weeks since you last fed your gardens, it’s time to do it again. Our Colorado soils are notoriously low...

May 31
1 min

Broken Branches

The wind storms we had this year has caused some branch breakage in my Autumn Blaze Maple. When is the best time to prune it out? A:...

May 31
1 min

Thinning Fruit Trees

My fruit trees are loaded with fruit this year. Is it a good idea to thin some of it out? A: Those of us with fruit trees are...

Apr 23
1 min

Should I feed my lawn in May?

A: If it has been more than four weeks since the lawn was last fertilized, apply slow release, high nitrogen lawn food this month. It is...

Apr 23
1 min

My tall growing flowers like peonies, dahlias, hollyhocks, gladiolus, lilies and salvia have a tendency to flop over by mid summer. How can I stop this from happening?

Trying to stake them after this happens makes them look weird and unnatural. A: Stake tall growing flowers that are prone to water and...

Apr 23
1 min

When can I set out my tropical houseplants that have been indoors all winter?

A: Houseplants scheduled to spend the summer outdoors should be kept inside until late-May or early-June when night temperatures stay...

Apr 23
1 min

When is it safe to plant potted roses out in the garden?

A: While there are no guarantees, mid-May is typically a safe bet but be prepared to cover newly planted, greenhouse grown roses if the...

Apr 23
1 min

I have a garden pond with hardy water lilies that stay out all year round. I’d like to add some tropical night blooming water lilies this year. How warm does the water need to be?

A: When pond water temperature reaches 70F. it's safe to set out tropical water lilies, water hyacinths, water lettuce, callas, water...

Apr 23
1 min

How soon can I start direct sowing flower seeds in the garden?

By Keith Funk A: Seed tender annuals like marigolds, zinnias, and cosmos directly into the garden by mid-May. Most all annual...

Apr 23
1 min

When is it safe to plant out warm season veggies like squash, peppers and tomatoes?

By Keith Funk A: April and May are excellent months for controlling Japanese Beetle grubs that overwintered from last fall. My personal...

Apr 4
1 min

When should grub killer be applied to control Japanese Beetles?

By Keith Funk A: April and May are excellent months for controlling Japanese Beetle grubs that overwintered from last fall. My personal...

Apr 4
1 min

When and how often should I feed my perennials?

By Keith Funk A: My first application of plant food on my perennials is in early April. I prefer a granular fertilizer with an analysis...

Apr 4
1 min

Are there any flowers I can plant outside in April for some extra spring color?

By Keith Funk A: Yes. There are several cold-tolerant annuals and perennials that will flower beautifully during our cool/cold spring...

Apr 4
1 min

What should I do when my early spring flowering bulbs are finished blooming?

By Keith Funk A: Remove spent flowers but keep all the foliage to rebuild the bulb’s strength to rebloom again next year. Show them...

Apr 4
1 min

When do I prune my flowering shrubs?

By Keith Funk A: Shrubs that flower before Memorial Day can be pruned immediately after flowering. These shrubs include lilac,...

Apr 4
1 min

When is the best time to lift and divide perennials?

By Keith Funk A: That depends on the plant. Most perennials can be lifted and divided now, in early spring as you see new growth...

Apr 4
1 min

When should I prune my raspberries?

A: Now. For fall-bearing raspberries like Fall Gold, cut all canes to within 6-8” of the ground. This type of raspberry produces fruits...

Mar 13
1 min

When should we divide our irises

When should we divide our irises? I have several huge clumps that don’t bloom as well as they used to. A: Irises (Tall-bearded,...

Mar 2
1 min

Harvesting Overwintered Root Vegetables

Q: We still have a lot of root vegetables left in the garden from last year. They are showing new growth. When can we harvest them? I...

Mar 1
2 min

Do Aphids Overwinter?

Q: I grow kale in a raised bed. Last year it got covered (smothered) in aphids. After using Neem oil spray on it for a month, I decided...

Feb 12
1 min

Beheaded Beans

Q: I planted a bunch of bean seeds July 1st and had very poor germination though I watered 2X a day. One of the four that did sprout was...

Jan 11
2 min

Get Amaryllis to Rebloom

My Holiday Amarylis is Spent. Now What? Q: I have a couple of Amaryllis bulbs that I kept after they bloomed the first year. I keep...

Aug 24, 2023
1 min

Shade Trees Dropping Leaves

Q: Our shade trees look gorgeous this year due to all the rain. The lindens and burr oak have unusually large, odd-shaped leaves. During...

Apr 14, 2023
1 min

Growing bell peppers in Colorado

Q: How do I grow a good bell pepper? My pepper plants never get as big as they should and the fruit is usually misshapen and small. We...

Apr 14, 2023
2 min

Ugly Lawn in Colorado

Our lawn has just gotten uglier every year. We’ve had it aerated most Springs but that isn’t helping much anymore. I don’t need it to be...

Aug 26, 2022
1 min

Struggling White Weeping Spruce

Q: I planted a beautiful white weeping spruce about on the west side of my garage in Denver in early May. It's struggling, maybe because...

Aug 25, 2022
1 min

Reliable Easy-Care Bulbs for Colorado

Q: What are some reliably returning, easy care bulbs for our region? A: When the bulb catalogs arrive, it’s so tempting to order the...

May 13, 2022
1 min

Leaf Miners on Swiss Chard

Q: Every year, our swiss chard gets a leaf miner problem, causing most of the leaves to go brown and wilty in parts, or sometimes entire...

Apr 12, 2022
2 min

Japanese Beetles eating Blackberries

Q: We planted primo-cane blackberries two years ago in a row next to our ‘Heritage’ red raspberries. Reportedly you can cut both of these...

Apr 12, 2022
1 min

What are the best patio trees for containers to provide shade?

Q: What are the best patio trees for containers to provide shade? (For Denver, CO elevation and climate)? A: When I first got out of...

Mar 3, 2022
1 min

Low-Water Shrubs

Q: What are some large shrubs for the low water garden? I need some ornamental varieties that get at least eight feet high. Width is...

Colorado Gardening Resources

SEED COMPANIES

Western Native Seed

Miss Penn's Mountain Seeds

FARMERS MARKETS

Southwest Plaza Farmers' Market

Littleton Farmers' Market

Lakewood Farmers' Market

Highlands Ranch Farmers' Market

EDUCATION

Keep It Clean Partnership

Growing Gardens

PLANT SELLERS

Long's Gardens Since 1905

Cold Hardy Cacti & Succulents

DogTuff Grass

PLANT SOCIETIES / GARDEN CLUBS

Denver Rose Society

Rocky Mt Chapter North American Rock Garden Society

Colorado Native Plant Society

PUBLIC GARDENS

Denver Botanic Gardens

Gardens at Spring Creek

Denver Botanic Gardens at Chatfield Farms

Plant Select

High Plains Environmental Center

GARDEN CENTERS & NURSERIES

Jared’s Nursery, Gift & Garden Center

Harlequin's Gardens

City Floral

Tagawa Gardens

Bookcliff Gardens

Fox’s Garden Supply

Southwest Gardens

Malara Gardens

Pine Lane Nursery

Phelan Gardens

The Flower Bin

Bath Garden Center & Nursery

Miss Penn's
Mountain Seeds

Southwest Plaza
Farmers' Market

Littleton
Farmers' Market

Lakewood
Farmers' Market

Highlands Ranch
Farmers' Market

Keep It Clean
Partnership

Long's Gardens
Since 1905

Rocky Mt Chapter
North American Rock Garden Society

Colorado Native
Plant Society

High Plains
Environmental Center

Bath Garden Center
& Nursery