5 gallons per plant per week in summer when there is no rain.

You can also think of that as one inch per week of rain.

If your soil is very very heavy and/or drainage is poor, somewhat less. If your soil is very light and sandy, and drainage is sharp, perhaps a little more.

In cool, overcast weather you probably won't need as much water as in sunny, hot weather. Do not be afraid to feel around in the soil where it is safe, to see if it feels moist. Moisture feels cool to the fingers.

The ideal is almost always moist, but never ever soggy.

But, you want to water less frequently, for longer periods of time so that the roots grow down to reach water. 30 seconds is not even close to long enough. Twice a week should be sufficient during dry spells, if you water deeply enough.

30 seconds means nothing in itself. Measure how many seconds it takes to draw a gallon or five gallons at the water pressure that flows through the tap that you use.

If you have medium to heavy soil, apply the 5 gallons once a week. If you have sandy or shallow soil, divide it into two smaller applications twice a week. Roses in pots or newly transplanted from pots may need water every 2 days.

Once well established, roses can go a long time without water, but they will stop growing after a couple of weeks with dry topsoil.

5 gallons/week would probably be needed only during the hottest Michigan weather. 3-4 gallons would be enough in spring and fall, or during overcast weeks.

Okay, great advice! I will count out how long it takes to fill a gallon and go from there!

I really appreciate the responses! I am loving seeing new growth on my roses and don't want to mess them up by over or under watering.

In my conditions, this much:

{{gwi:295920}}

To avoid the water coming out too fast and running off, I use a five gallon bucket with a 16d nail hole or 1/4 inch hole in the bottom side. As it runs out it all soaks in with little, if any, run off.That way you're sure of getting the five gallons on each bush.
Avoid carrying a full five gallon bucket by placing the empty bucket next to the rose and filling it quickly with a garden hose.

Yes, or you can build a dike around each plant that will hold a couple of gallons and just go around the garden twice with the hose on full.