Question
our impatients are dying in our flower boxes, they seem to rot at the root.  at first we thought too much water, but cut back, and they still die.  What flowers are best for flower boxes facing the ne

Answer
Impatiens are great flowers for boxes facing NE - Let me ask a few questions that might answer why these plants aren't doing well.
1. Are there drainage holes in the boxes?  If not, the soil will stay too wet and rot the plants.
2. Is there new potting soil in the boxes?  Old soil is often filled with last year's roots, which clog the drainage holes, so that the new plants can't get established quickly and the soil stays too moist.
3. Did you put soil from the garden into the boxes?  Dirt from the garden can not only be heavy, but filled with various fungi that can cause root and crown rot. The best thing to do is use new potting soil every year.
4. Watering: if the weather where you live is still cool at night, you have to water less often. If the weather is above 75 both during the day and at night, you might have to water every day but test the soil before watering.  Water in the morning whenever possible, and soak the soil well. Don't water again until the soil feels dry, or looks like it's pulled away from the sides of the boxes.

Once rot starts it's hard to stop, so if the roots were rotting they might have continued to rot even when you altered the watering. The fungi start growing, and continue to grow even if you're no longer watering as much.

If I were you I'd start over with new soil and plants - Impatiens are great! - with drainage holes etc.

all the best,
C.L.