Colorado_medium Colorado Extension

Questions received for Colorado through Ask an Expert.

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Questions asked to this group

Sunflower Rust

After some extensive research, I've found that my wild sunflowers' leaves undersides are covered in rust fungus. I've been pulling them for the end of the year, but I want to help it from coming back again in the future. I've also heard that it overwinters easily, and I mulch with the stalks. What can I do to alleviate the problem now, and in the long term? If there's a good organic solution, I'll go with that, otherwise, I'm willing to resort to chemicals to deal with the problem.

Larimer County CO Posted about 2 hours ago

Plum tree leaking sap

We have a fairly young plum tree. This summer we noticed sap leaking from the trunk. The sap leakage is only on one side of the trunk. We showed a photo of it to a staff member at the garden center where we purchased the tree two years ago. They suggested that we were over-watering and stressing the tree - and that the sap was likely a reaction to insects drawn in by the trees weakened condition.

We can not see any insects, and we have decreased the watering of the tree. The leakage has gotten worse. Due to spring frost, the tree did need to grow leaves a second time. I included photos of the sap on the trunk, the leaves, and the whole tree.

What is your opinion about the tree problem? How can we correct that problem?

Douglas County CO Posted about 5 hours ago

Sick Miss Kim Lilac

These are pictures of a sick Miss Kim Lilac. These are 3 new shrubs planted in May 2017 in a river rock bed. Bed is south facing in front of a white vinyl fence. Each plant is on a functioning drip system. Leaves are curled inward, purple on the outside and green inside. The leaves feel dry and brittle to the touch.

When first planted, each plant had some blossoms.

I first tried a copper fungicide with no effect. On advice of Fort Collins Nursery used 0-10-10 supplement for past two weeks. 2 oz, per gallon applied according to directions.

I can't help but feel that these plants won't make it through the winter. Any advice?

Larimer County CO Posted about 6 hours ago

Black spot fungus on maple leaves

I have a large silver maple in the backyard that is about 40 feet tall and covers one half of the yard. Many of leaves developed black spots the second half of the summer. I estimate that about 1/4 to 1/3 of the tree's leaves have the fungus. Although a website I read when I googled "black spots on maple leaves" said that the infection would not hurt the tree, that does not make sense, because the leaves turn yellow and curl up. If the entire tree becomes infected with the fungus next year I doubt that it would be able to produce the energy for the tree to survive. So, my question to the tree expert who responds to this post is: If this were your tree, what would you do?

Sincerely, Jackie Bedwell

Boulder County CO Posted about 6 hours ago

ZZ plant

I've been told two complete opposite ways to keep a ZZ plant thriving and healthy. Filtered light, dry out between waterings and/or bright light and keep moderately moist?

Also, for years I've had healthy rubber plants by putting them in low light and very little water. I had one for 10 plus years and suddenly it died. The new ones I've looked at, the tag says the opposite, to put in filtered light and water once a week?

Jefferson County CO Posted about 19 hours ago

Brwoned Grass Pulling Out in Clumps

Thanks for your time. I have a great front lawn. My back lawn, however, has large spots (6 x 10) that have turned brown and lost all roots. The grass pulls up with no effort and shows no root system. I have checked for visible bugs and grubs. I found nothing but a few earthworms. I have watched the watering system and checked to be certain that the lawn has been watered correctly. I'm thinking "maybe fungus", but I don't know how to ID which one it might be. Any advice or thoughts. Thanks!

Terry Timm
1413 Silk Oak Dr, Fort Collins

Larimer County Colorado lawns and turf Posted about 23 hours ago

Irish Soda Bread Muffin Recipe

I'd like to make some irish soda bread muffins but I know they won't turn out unless I modify the ingredients for higher altitude. The reicpe calls for 2-1/4 cups flour, 1/2 cup sugar, 2 t baking powder, 1/4 t baking soda, 1 egg, 1 cup buttermilk, 1/4 cup butter, 1/4 cup canola oil..........among other ingredients.
I know they should be baked a hotter temperature & shorter period of time but I'm uncertain about reducing and/or increasing the above ingredients. Can you help? Thanks

Weld County Colorado Posted 1 day ago

"Grass" sprouting in my garden! Weed? How to get rid of it?!

Hey! I have recently moved into a house in Northern Denver. This "grass" looking plant(s) started sprouting up in my garden! I have NO IDEA what it is, how to get rid of it, and it's started taking over! Please help! Pulling it out is DIFFICULT, because it just breaks off at the's like pulling out regular grass with how hard it is. It's NOT crabgrass, it's not quackgrass, and it just came up in early September. I don't know if it'll sprout into a plant or not...but for now it just looks like thick-bladed grass clumps! Have considered Roundup, but a lot of it is in amongst my other real plants that I don't want to kill!! Please help!!

Weld County Colorado Posted 1 day ago

wintering over potted ornamental grasses

We live in a townhome community and are limited what we can do with planting ornamentals. One solution that is allowed is to plant potted items. We planted two varieties of Feather Reed Grass in two separate pots. My question is, how do we winter these over so they could be expected to survive the winter. The pots are approcimately 2' high and 20" across. We are in far SW Denver County.

Denver County Colorado Posted 1 day ago

Will weeping redbuds grow on the front range?

I am looking for a flowering small tree for our yard in Arvada. I saw an advertisement for a Lavender Twist Weeping Redbud and wondered if it would grow here.
Thanks, Ruth Konda

Jefferson County Colorado trees and shrubs Posted 1 day ago