My yard has a lot of pines plus a lot of sun on a hill side or more like a sloping yard.
Poppies require a good amount of sun, and soil close to neutral pH. Therefore, consider where you plant in order to get maximum sun for the poppies, and you may need to add lime to neutralize the acidity in soil from decomposed pine needles. https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-poppy-flowers.htm
When the poppies go dormant, do I cut the pod and cut back the stem? The oriental poppy is already dormant. I snipped the pod off...not sure if this was the right thing to do. Do I cut the stems back? If so, where should I cut it? I read that you should cut the stems 3" from the ground.
You can just let the leaves die back on their own or cut them back if you want a little neater look to your garden beds.
Cutting the pods away will stop them from reseeding. Shake the seeds onto the ground if you want to increase your Poppy beds.
Here is a link about Poppies.
https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-oriental-poppies.htm
I have very healthy poppies. Is there anything I should do in the fall, like deadheading?
Here is a link that will help.
https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-oriental-poppies.htm
When my poppies have finished flowering in July, can I cut off the poppy heads or should I leave them for a while? They start to look very untidy and I'm not sure how long I should leave them before cutting them back.
Poppies are beautiful when in bloom and then the garden beds tend to look untidy and empty when they finish flowering.
Some people plant some additional perennials in the beds to fill in for the rest of the season. This works well to companion plant with the poppies.
You can leave the seed heads attached to allow more seeding, or remove them.
As the plants wilt down they also can be just left, but you can also clean up the wilted leaves if you like.
https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-poppy-flowers.htm
My poppies have bloomed. Should I cut back the flower stem now or let it be?
You can do either. Scatter the seeds if you want to help reseed the poppies.
Many gardeners like to trim up the beds to neaten things up for the remainder of the season, but you can just leave the stems and leaves to die down.
https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-oriental-poppies.htm
Me and my friend are new to gardening. He has a small area, 3' by 9'. It receives about 3 hrs. of sun on the left half and all day full sun on the right. Last spring we added mulch and tilled the soil. I planted poppy flower seeds a few months ago, and on the advice of online forums, only misted the seeds until they started to germinate. Once sprouted, I would water the garden normally, no deep watering. Now the flowers that bloomed grew sparse and stunted on the left and are now drying out on the right. We dug the soil to check it and found it hard, compacted and dry just below the surface. After watering for a few minutes, we dug again and still no seepage. The soil remained compacted and dry just below the surface. We are unsure what to do next. Do we wait until fall and till the soil, but will it become compacted and dry even after watering in a few weeks? Or remove as much soil as we can and add new soil, but the cost? Thanks for your time.
This article should help: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/improving-compacted-soil.htm
Will my poppies eventually take over the grass in the garden? I have gorgeous poppies - lots of them, more every year. I also have lots of ugly grass growing between all the poppies. Eventually, the grass is taller and the poppies are dormant, and it all just looks bad. How can I get rid of the grass without hurting the poppies? We moved into this garden, it's not one I planted, so I'm really not sure what to do other than to dig it all up and re-plant next year, but I really, really, don't want to do that!
Weeds among poppies can be an issue, especially in your case where it was not cared for.
Poppies will spread but in your zone 4 garden you will likely lose some each year also, so a takeover is not likely.
You can try planting other flowers among the poppies to help you fill in the garden after the poppies are done.
A ground cover that will help suppress weeds could be quite attractive.
Either way it's some work ahead for you.
Best of luck!
https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-oriental-poppies.htm