That's mugwort, Artemesia vulgaris. It's very invasive. It spreads by underground rhizomes and even small pieces of the rhizome are capable of sprouting another plant. I hope you've caught it before it spread too much. I've been pulling it for 10 years.

Jeanne is ABSOUTELY right! It is NOT scale but the results of a bad mite infestation. That is what they do to the leaves and the white colored/pitted leaves are permanently like this after the damage is done. Believe me, I have had a lot of experience with these buggers in the last year and they DO spread. You must segregate this plant immediately or cut off those bad leaves. Once these guys spread they are very tough to get rid of. It was a nightmare for me. I have them under control now by using a natural spray made by Doktor Doom (don't know if its available in the US though). As soon as you see these markings on any of your other plants make sure you treat them immdediatly. The new leaves should come in fine after you eradicate them. Check all the othersides of your other plants...they seem to like Phal's the most but I've had them on Catt's and Dend's as well. Good luck! Teresa

Agreed - Juniperus virginiana. I wouldn't call them invasive just because they regenerate via bird droppings. Personally, I love finding conifer volunteers on my property. If they are in the wrong spot, just pull them out or transplant them elsewhere.

Google "Mugwort" and see if that matches your plant. Several other things resemble mugwort, so I am not sure. However, if that is it, it's evil. Get rid of it. It spreads by extensive rhizomes. Pull it up; it's immune to most weedkillers. Get every little bit of it, and then check multiple times over the growing season and pull it whenever it rears its horrid little head. I have a bad mugwort problem and it's nearly impossible to get rid of once it's established.