Native Plants

Q. Who is Mr. Smarty Plants?
A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

rate this answer

Friday - June 19, 2009
From: Shelby Twp, MI
Region: Midwest
Topic: Invasive Plants, Compost and Mulch, Trees
Title: Removal of invasive horsetail in Shelby Township, MI
Answered by: Barbara Medford
QUESTION:
Please help me or direct me to who may be able to help. I have horsetail (Equisetum) invading my Blue Rug Juniper. Please tell me what I can use to get rid of the horsetail (Equisetum) without killing off the Blue Rug Juniper. Thank you so much for your time and effort.ANSWER:
There are 11 species of the genus Equisetum native to Michigan; we have chosen Equisetum hyemale (scouringrush horsetail) as a representative species to use as an example. Blue Rug juniper is the cultivar 'Wiltonii' of Juniperus horizontalis (creeping juniper), also native to Michigan. So, we can understand your having both plants in your garden, as both are native; what we can't understand is why they are growing close enough together to be interacting. Equisetum hyemale (scouringrush horsetail) (and the rest of the genus) are very much wetland plants-they tolerate shade, poor drainage, occur in wet places and even standing in water. They are considered very aggressive, which you have already found out. Juniperus horizontalis (creeping juniper) is intolerant of shade and poor drainage, needs dry soil and does best on dry, sunny hillsides. If the Equisetum is competing successfully with the juniper, then it's obvious the juniper is in the wrong place.
What to do? The first and most obvious solution would seem to be move the juniper, if that is at all feasible. If it is too large to move or there is no other more suitable spot in your garden, you will need to amend the soil, and perhaps prune back trees to provide more sunlight. Either way, you are going to have the get the horsetail out of the juniper, and the only way to do that is by pulling it out, and keep on pulling it out. It spreads by rhizomes, shallow underground roots. Most plants that spread that way are happy to snap off at the ground when you pull them, because those underground rhizomes are down there with food stored up ready to resprout the plant.
To amend the soil for the juniper, you must improve the drainage. The best way to do this (without digging them up and getting them into a raised bed) is to work compost or some other organic material into the soil and continue to do so periodically. Also, mulch the soil, without covering the crowns of the juniper, with a good quality shredded hardwood bark mulch. This could help suppress the horsetail, although it's unlikely. The main benefit of the mulch is that it will protect the roots of the juniper from heat and cold, and as it decomposes it will continue to add to the organic content of the soil and improve drainage.
Pictures of Blue Rug juniper
More Trees Questions
Protecting a non-native Meyer Lemon from Freezing in Austin
January 05, 2013 - What is the best way to protect my Meyer Lemon tree from freezing Austin weather? It has been planted in my yard for 1 year and is about 4 feet high
view the full question and answer
Water requirements for fruit trees in California
January 15, 2013 - Dear Sir;
In which of these options (fruit trees) the need for watering in irrigation process is higher than the others:
-Olive tree
-Nectarines and peaches trees
-Hazelnut trees
-Pistachios and ...
view the full question and answer
Why is my 3 year old Redbud not flowering in San Marcos, TX?
March 24, 2010 - My Cercis canadensis var. mexicana, purchased at the Lady Bird Johnson Wildflower Center, is 3 years old, very robust, but has never bloomed. Any explanation?
view the full question and answer
Shade tree for Southern California
November 14, 2013 - I had to cut down my huge ficus tree for several reasons, however it provided lots of shade, that we miss. Can you help me find a good shade tree with non-invasive roots that is good for growing and p...
view the full question and answer
Deer resistant, shade tolerant trees for part shade in Highland MD
March 29, 2013 - Deer resistant privacy trees for partial shady area in Highland, MD.
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |