Looking for a suitable tree for the garden

Hello dear forum community

we are looking for a suitable garden center for our garden.
We already planted 2 maple trees about 3 years old in our garden in the spring, as well as a smaller one from a pot which we transplanted into the garden soil in the summer. Unfortunately, all 3 trees died over the course of the year. One of the two larger ones sprouted nicely in the spring and also turned green but then lost all its leaves around July. The second one had very few shoots and also quickly lost them all again. The small one grew wonderfully in the pot for over a year, green and strong, but also died after only 2 months. All general planting instructions (from the nursery) were followed, such as hole size, watering behavior, etc., but it didn't help.

We suspect that our soil is simply too wet. The garden area was excavated by about 30 cm and filled with topsoil. The excavated soil as well as the soil underneath the topsoil is hardly permeable to water; it takes ages for water to seep away there (during the construction phase). For example, in order to set up our fence, I had to loosen the soil with a pickaxe as well as an electric chisel to be able to dig it out. To alleviate this somewhat, we also installed a drainage system in the garden for water drainage. However, since the holes for the respective trees are deeper, we think rainwater collects here and cannot seep away, so the roots rot and the trees died.

We now want to redesign the garden with plants that can tolerate waterlogging.
For this, we are looking for a tip for a suitable garden center which can also tolerate moisture, is not too small, and, of course, still looks good.

Maybe someone can help us and also has a tip for suitable other plants.

Thank you very much

The first trees that come to mind are alders. They often stand in water. Willows should also be an option - there are also smaller varieties (basket willow?). The big question, however, is whether that was really the reason.

I have also read about alders, but they are supposed to sprout from their seeds. We are quite sure that moisture is the reason because we also have other plants and shrubs in different beds that had roots that were really rotted and therefore died. We live in Schleswig-Holstein and especially this year we have had a lot of rain.

Difficult soils are often the reason why only a few varieties grow. However, this is not a disadvantage! A garden with few varieties but strong healthy plants often looks better than a colorful collection of weak stuff.
It is best to see what grows well with the neighbors.

For example, you can also create very beautiful gardens with bamboo. There are also varieties that do not spread in all directions and are very nice. A gardening friend of mine has some and knows quite a bit about them. If needed, I am happy to ask for the names.

so that would be nice :-)

with the neighbors it is still difficult because it is a new development area and everyone is more or less at the same level or does not place much value on the garden in terms of plants.

A garden with few varieties, but strong healthy plants often looks better than a colorful assortment of weak stuff.

The mix makes the difference, ideally the plants and trees repel each other’s pests. The communication between trees, fungi, etc. is also an interesting field – there is information about this in the books by forester Peter Wohlleben. But "back" to the original question. I do not believe in the success of the method of looking for the "right" water-loving tree for a sponge soil. On the path to the realization that the drainage is relatively high, I would rather move on.