Thank you both! Black medic is exactly what it is. It is such a common weed that I'm surprised that the NCSU database doesn't have it in it. :: sigh ::

Even though native and well-adapted to local growing conditions, newly planted shrubs need a period of time to become established before they can be assumed to be 'self-sufficient'. That would extend through at least one full growing season - often a longer period is required. "Some rain" is very likely not enough water if you have not been regularly irrigating them as well. You can check to see if the ailing plants are truly dead by scraping off the bark on a lower stem or the trunks. If it shows green underneath, the plants are still alive and may benefit by pruning back hard to let them regrow (with adequate watering!!). I'd avoid using any fertilizer at this point - when plants are under stress for whatever reason, they are unable to metabolize fertilizers properly and applying it unnecessarily will only stress them further. If it is not green, then they are indeed dead and will need to be replaced. New plants will require regular deep watering during the period of establishment - do not rely simply on rainfall. It is not enough. The other thing you should check is depth of planting. Many newly planted shrubs and trees fail because they have inadvertantly been planted too deeply.

If you are living in an area that has had a dry summer and fall, then the secret is to provide water! Install only those plants for which you are able to provide proper care throughout their establishment period. I, too, live in an area that has been terribly dry for many months, but have made sure that all plantings get watered as needed. If you live along the coast, there are other problems associated with that kind of environment so be sure that you are selecting the right kinds of plants for your location. If you are looking for more detailed advice, perhaps you could be specific about what the problem seems to be.

What Jane said, but IMO you may want to replace the string with a twist-tie or something that will not 'cut' into the plant as it grows. It will be very helpful to get it supported so there is minimal movement for the next several months while roots develop and 'dig-in' to the media. Root-wise, there is not much to work from there, so don't be too disappointed if it doesn't survive, happens to all of us :( . Good luck, Bob