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Gardening Q & A
Read our Q & A postings with Keith Funk answering common Colorado gardening questions here. You can also hear him on the Garden Wise Radio Show on Legends 810AM, every Saturday morning from 7-9. Special thanks to Kelly Grummons who answered these prior to 2024.
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.
4 days ago1 min read
When to start seeds indoors in Colorado
Q: I’d like to start some vegetable seed indoors this year to save some money. When should I start? A: My go-to answer is sow your seeds...
41
4 days ago2 min read
Japanese Beetle Resistant Roses
Though repeat-and ever-blooming roses have become all the rage, growing varieties that bloom once in early/late spring & early summer...
22
4 days ago1 min read
When to plant wildflower seeds in Colorado
Q: When is the best time of year to direct sow wildflower seeds outdoors here in Colorado? A: Late fall through early winter is a good...
39
4 days ago2 min read
What is an heirloom plant?
A true heirloom comes true from seed, has been nurtured, selected, and handed down from one family member to another for many...
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Dec 2, 20241 min read
How to Grow Paperwhites
Q: What’s the best way to grow Paperwhite Narcissus? A: One of the most popular methods is to choose a water tight, fairly shallow...
17
Dec 2, 20241 min read
Overwintering Potted Japanese Maples
Q: I have a Japanese Maple in a large pot. I understand it is risky trying to overwinter potted trees, shrubs and perennials in their...
24
Dec 2, 20243 min read
Online Seed Sources: Hard to Find Seeds
Q: I’m looking for odd and interesting vegetables, rock garden plants, and perennials, and I feel like I’ve exhausted my local retailers....
115
Dec 2, 20242 min read
Voles in Lawn?
Q. Once the snow melted from that last big storm I notice mounds of soil, shallow burrows and meandering, shallow runways in the lawn...
99
Nov 1, 20241 min read
Autumn Blaze Maple Tree Care
Q. I planted an Autumn Blaze Maple last year. Do I need to wrap the trunk again this year? A. Young, thin barked trees like maples, ash,...
56
Nov 1, 20241 min read
What should I do with my Amaryllis this time of year?
A. I bring mine indoors at the very last minute before the first predicted frost. I feel like they benefit from the cool nights...
39
Nov 1, 20241 min read
Care of Streptocarpus Plants
Q. I’ve been trying to grow Streptocarpus, aka Cape Primrose. They keep dying on me but I’m told they are easy. What am I doing wrong?...
149
Nov 1, 20241 min read
Watering Bulbs in Winter
Q. I planted lots of spring flowering bulbs this fall including tulips, daffodils and crocus. I watered them in thoroughly after...
75
Nov 1, 20241 min read
Winter Watering in Colorado
Q: I planted quite a few perennials, some shrubs and a tree this year. Should I water them during the winter and how often? A. Our...
70
Sep 30, 20241 min read
Drainage Rocks for Potted Plants?
Q: When transplanting potted plants, is it a good idea to add a layer of gravel at the bottom of the pot to ensure good drainage? A:...
81
Sep 30, 20241 min read
Storing Dahlias, Cannas and Begonias
Q: How do I store tender bulbs like dahlias, cannas and begonias for next year? A: In a dry climate like Colorado, storing tender bulbs...
90
Sep 30, 20241 min read
When to prune back shrubs like butterfly bush, roses, and bluemist spirea?
Q: Can I prune back shrubs like butterfly bush, roses, and bluemist spirea in the fall or should I wait until spring? What about clematis...
99
Sep 30, 20241 min read
Do I cut my perennial flowers and grasses for winter?
Q: Do I cut my perennial flowers and ornamental grasses back in the fall or the spring? A: In general, it doesn’t really matter to the...
66
Sep 6, 20241 min read
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...
171
Sep 6, 20241 min read
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...
113
Sep 6, 20241 min read
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...
114
Sep 6, 20241 min read
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...
203
Jul 28, 20242 min read
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...
200
Jul 27, 20242 min read
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...
59
Jul 27, 20242 min read
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...
131
Jul 27, 20241 min read
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...
111
Jul 6, 20241 min read
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...
309
Jun 28, 20241 min read
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...
272
Jun 28, 20241 min read
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...
595
Jun 28, 20242 min read
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...
120
Jun 28, 20241 min read
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...
46
Jun 28, 20241 min read
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...
166
May 31, 20241 min read
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...
259
May 31, 20241 min read
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...
66
May 31, 20241 min read
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...
106
May 31, 20241 min read
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:...
32
May 31, 20241 min read
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...
68
Apr 23, 20241 min read
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...
63
Apr 23, 20241 min read
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...
562
Apr 23, 20241 min read
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...
78
Apr 23, 20241 min read
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...
27
Apr 23, 20241 min read
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...
31
Apr 23, 20241 min read
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...
77
Apr 23, 20241 min read
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...
70
Apr 4, 20241 min read
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...
1,781
Apr 4, 20241 min read
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...
163
Apr 4, 20241 min read
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...
184
Apr 4, 20241 min read
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...
79
Apr 4, 20241 min read
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,...
105
Apr 4, 20241 min read
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...
74
Apr 4, 20241 min read
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...
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