How to kill this plant
I have this plant of which leaves are like bamboo and yellowish roots grow horizontally. Please see attached pictures. Because it grows under and mingle with an azalea now, it is impossible to uproot it without dig up the entire azalea. Is there any way to kill it without hurting the azalea bush? Are there something I can apply to its leaves and kill it? What is the name of this plant? Thank you very much for your help.
Montgomery County Maryland
This looks like one of the pygmy or dwarf bamboos that are sold as a ground cover. They are aggressive and should not be planted. Bamboo is designated a non-native invasive plant in Maryland, so you'll be doing everyone a favor by getting rid of it.
You need to use a systemic herbicide on bamboo, because systemics get down into the root system and kill it. The recommended ones have the ingredient 'glyphosate'. This is a common herbicide ingredient (though originally only found in Round-Up.)
However, glyphosate is a total vegetation killer--so you cannot spray it on your bamboo without killing your azaleas--unless you can spray it in such a way that the spray does not contact the azalea. Normally, we recommend using a shield of cardboard or plastic between your desirable plants and the target plants to keep the herbicide off the desirable plants. You may be able to do this for most of the bamboo. For bamboo that is too close to the azaleas, you can wet a sponge or cloth gloves (over impermeable rubber gloves), saturate in the herbicide, wrap them around the bamboo stem by stem and run up the stems.
This is labor intensive--but you don't have a lot of options.
Here is our websites info on bamboo, including eradication methods--timing is very important with bamboo and be absolutely sure to do both applications: http://extension.umd.edu/learn/bamboo-hg28