Master Gardener – Answers

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Crepe Myrtle Bark Scale
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Date Posted: Thu, Feb 08 - 3:03 am
- Hello! Would you be able to recommend the best product for treating a severe case of Crepe Myrtle Bark Scale? The tree is about 5 years old and has been very healthy until last year when it got the scale. I have heard that it is best to treat with a systemic insecticide in the spring but there are a lot of products out there and the prices very quite a bit. Also if there is a better way to treat than an insecticide please let me know! Also a lot of the products recommend a treatment based on the trunk size if the crepe myrtle has multiple trunks do I add all the trunks up or should I treat based on a single trunk size? Thank you so much !
- These are great questions about Crepe Myrtle Bark Scale CMBS). I had to do a little bit of research myself to figure out how to best give you some guidance. A systemic insecticide in the spring does seem to be the recommended treatment. A soil drench of imidacloprid or dinotefuran is recommended when crape myrtles begin to leaf out in the spring, usually around April. Personally, I've had success with Bonide products and find them to be available at many local garden shops. Bonide has an annual tree and shrub product that has an active ingredient of imidacloprid. (Other insecticide recommendations from the extension office are available here: https://www.pubs.ext.vt.edu/456/456-017/456-017.html) If you decided to go with an insecticidal soap spray, just be sure to refrain from applying it when pollinators or other beneficial insects such as ladybird beetles are present on the trees. Here are some guidelines for measuring the circumference of the tree trunk: 1. If it appears that a tree actually represents two or more trees that have their trunks pressing together, we measure the largest trunk. 2. If it appears that the tree tree is a single tree that splits below 4.5 feet, we measure at the narrowest point between the split and the ground. 3. If it appears that the tree tree is a single tree that splits above 4.5 feet, we measure the trunk at 4.5 feet. If you would really prefer to stay away from insecticides, another control option is to lightly scrub the main trunks of crape myrtles with soapy water made with mild dish detergent and a stiff-bristled brush to kill and remove CMBS. This also removes some of the sooty mold and the loose exfoliating bark that shelters CMBS, exposing the scales to any spray treatments that may be applied. And finally, its important to check and be sure your control methods are working. To asses if a control treatment was effective or not: check for live CMBS by running a fingernail over the scales and looking for a pinkish-red fluid. Dead scales will be dry, but their white bodies may persist on the trunk and branches of crape myrtle until they weather off.
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English Ivy control & replacement
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Date Posted: Thu, Feb 08 - 2:21 am
- Hi there! I have a bunch of English Ivy in my sunny, south facing backyard in the neighborhood behind Pony Pasture. I'm interested in replacing it with a Native Species but want to make sure that I am replacing it with the right species for the space. It is on a downward slope towards the house-so I'm not sure if it is providing necessary runoff to protect the house. Do you have any recommendations for what species to use and any tips on how to work on replacing it? Thank you so much! Katie
- Katie, I'm sorry! English Ivy drives me crazy. I spent the first year in my current house attacking the ivy in my back yard. My best recommendation for removal is to pull it by hand after some rain when the ground is moist. It will come up a little bit easier that way. And just attack it in sections. Its better to be thorough and take a little longer than to rush through if you really want the chance to keep it away. After that first year, I've just done a little bit of maintenance each spring to pull out any that starts to grow, mostly because it creeps back in from my neighbors yard. The Virginia Native Plant society has a great document with several options for English Ivy replacement that can be found here: https://choosenatives.org/wp-content/uploads/2020/07/Alternatives-to-English-Ivy.pdf Good luck and happy gardening!
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Interviewing a Master Gardener
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Date Posted: Wed, Jan 31 - 3:09 am
- Hello! My name is David Lefkowitz, I'm a reporter with RICtoday. I'd like to conduct an interview with a Master Gardener in Richmond on planting in the region, to run at some point in late February. Would somebody be available for such an interview in the next couple of weeks? Thanks!
- Hi David! Thank you for your inquiry. I will e-mail you directly to pass along contact information for one of our Master Gardeners.
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Native Dogwood and Holly
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Date Posted: Sat, Jan 27 - 3:05 am
- Two questions about native plants: are red twig dogwoods native to VA? I have seen dogwoods with red twigs in the woods, but never like the ones you see around cities or in people's yards like "arctic fire" with the really red branches. Besides the nativeness of red twig, do they need a lot of sun or can they do well in partial shade? Also, is holly native to the eastern us or is it naturalized nowadays and brought over by the colonists? Thanks, Neal
- Hi Neal! Great questions, I'll do my best to answer them. What most people refer to as "arctic fire" I think is the red-osier dogwood (Cornus stolonifera Michaux). The nativity of this species in Virginia is questionable. It was historically reported to grow along the Potomac River in Fairfax Co., but supporting specimens currently appear to be lacking. It tends to do best in full sun to part shade with moist, rich soil. In nature, it is most often found growing in wet swampy areas. The silky dogwood (Cornus amomum P. Mill.) has a red/purple twig and is native to our area. American Holly (Ilex opaca Aiton var. opaca) is native to our area! It is common in the Coastal Plain and Piedmont areas but infrequent in the mountains. The digital Atlas of Virginia Flora is a great resource for checking what is native to our area: https://vaplantatlas.org/index.php?do=start&search=Search
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Soil test kits
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Date Posted: Thu, Dec 28 - 3:33 pm
- Hello! I live in Richmond and would like to get a soil test done. Are there any free programs like the one for Henrico County residents?
- Most of the Richmond Public library branches should have soil test kits in stock. You can call ahead or stop by to ask for one. If you need any more information about getting good samples the Virginia Cooperative Extension has a great resource here: https://www.soiltest.vt.edu/content/dam/soiltest_vt_edu/PDF/urban-sampling.pdf Happy gardening!
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Master gardener classes and certification
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Date Posted: Wed, Dec 13 - 1:28 am
- Does Richmond offer Master Gardener classes and certification?
- Thank you for your interest in becoming a Master Gardener. I wish we were able to bring you on through the City of Richmond, but unfortunately the city does not have an extension agent in place and we are not sure when or if the position will be filled in the future. Without an extension agent in place, the current Richmond Master Gardeners are all volunteer lead, but unable to offer the training course. We are hoping to be able to offer the classes in an online version in connection with other counties in the future, but do not have any solid plans for that currently. You can reach out to the other counties to see when they will be offering classes if you would be interested in going through them to complete the program. Once a master gardener has completed the training process, you are able to transfer to a different locality if you wish.
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Composting - continued!
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Date Posted: Sun, Nov 12 - 5:36 pm
- I am very appreciative of the options you recommended for me to compost. I think I was not very clear in my question. I already know where to bring food scraps, and I already do bring food scraps for composting. My dilemma is where to bring dead plants. I have a tiny yard, and, therefore no space for a compost bin. Now that summer potted plants are dead, I need to know where to bring the large dead plants. Thanks
- I'm sorry my first answer did not give you the information you were looking for. I've reached out to a few others in our Master Gardener group but none of us have used a composting service specifically for large plants. I believe some of the suggestions I gave you may be able to take them, but the next steps would be to reach out them to ask. I did try to reach out to Richmond Grows Gardens, but have not yet heard back from them. I have previously spoken with some of the ladies that work at the Bird House Farmers Market and she shared that the compost company that picks up their bins can compost anything and everything organic. At the time, I didnt ask specifically about large plants, but here is the email address for the company if you would like to reach out and ask: info@nopeva.com I admire your determination for finding a good place to take these plants! I currently have a small pile in my back yard where they are breaking down, but it would be great to have other options available. Hope this information helps you get to what you are looking for!
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Composting Options
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Date Posted: Fri, Nov 10 - 12:55 am
- im wondering where i can bring pretty large seasonal plants that have been in pots and are now dead. can i bring them somewhere to be composted? is there a service the city of richmond offers on a regularly scheduled basis? i am new to richmond. thanks so much.
- First of all, welcome to Richmond!! And thanks for thinking about composting! The city does have compost collection sites where you can drop off your materials to be composted: https://www.richmondgrowsgardens.org/composting and there is an additional drop off site at the Bird House Farmers Market: https://birdhousefarmersmarket.org/info. There are also a local services that will do compost pick ups if that is a service your are interested in: https://enrichcompost.com/ or https://compostrva.squarespace.com/ thanks again for thinking about composting!
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Browning Dwarf Arborvitae
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Date Posted: Wed, Oct 11 - 12:47 am
- Dwarf Arborvitae has brown sections, on am effort to cut them out, it appears black underneath. What is happening? Thank you.
- I'm sorry you are having these concerns with your Dwarf Arborvitae. The first thing that comes to my mind is canker. Canker is infected wounds in the branches caused by fungi. Wounds can be caused by pruning, storm damage, cold damage, or excessive wetness. In plants with canker, you will observe yellow to reddish-brown branches in the middle of healthy green branches. Closer to base of the branch you may see slightly sunken, reddish cankers with profusely exuding resin. Black pustule-like fruiting bodies known as pycnidia may be seen breaking through the bark. There is no real treatment for canker stem diseases. The fungus survives in infected bark tissues, so it is best to prune all infected branches about 3-4 inches below the canker area. Spread of the fungus can be minimized by sterilizing any blades used between all cuts with a 10 percent bleach or 70 percent alcohol solution. Try to prevent damage to trees. Stressed and wounded plants are more likely to be infested. It is best to keep dwarf trees as open as possible so that they will dry out after rain. Prune to allow air flow in plants. Clean out leaves from the insides of shrubs. Do not bury plants too deep in mulch. Prune out infected branches and fertilize affected trees if needed. Good luck!!
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Japanese Spirea
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Date Posted: Tue, Oct 10 - 5:24 pm
- My japanese spirea has large dead sections that I just trimmed back. I don't see any bigs. Any ideas? And should this be cut way back in fall?
- Maintenance pruning for spirea can be done anytime of year and damaged or dead branches should be removed as you see them. When removing these branches, be sure to prune back to a point where the branch is still healthy, or back to the ground if the damage occurs throughout the length of the branch. An overall pruning can be done in late winter, just before new leaves begin to appear. Dwarf varieties (which typically grow 1-3ft tall) can be cut back to 4-6" above the ground. Taller growing varieties can be cut back to 10-12" above the ground. Without more information, it is difficult to say what might be causing the dead sections on your plants. These plants do not require a lot of water, and typically do well on rain water alone unless there is an extreme period of drought. You could monitor your soil to be sure it is draining well and not staying too soggy and moist which could lead to disease issues. One thing to keep in mind about Japanese spirea is that it is a non-native invasive plant. It has small seeds that can last for years in the soil making it very difficult to control. Once Japanese spirea is established outside of its intended areas, it can quickly crowd out native species. Unfortunately, the best control method is to remove existing plants. There is a native spirea that could be considered as a replacement: white meadowsweet (Spiraea alba). I hope this information helps you! Happy gardening!