Hi. I live in southeastern michigan (zone 5) and I also have pretty crappy
clay soil that I've slowly been amending each year. I've noticed that my
perennials come up much later (at least a month) than they do in areas
surrounding me. I also live about a block away from a large lake and my
temperatures here are slightly lower due to lake winds etc. Are the
slightly cooler temps causing a slower emergence of my plants or is it
possible that the toughness of my soil is causing my plants to fight to get
through so much that they take longer? (Once they make their appearance
they are healthy.)

Also, I've been kicking around the idea of just digging up everything,
throwing all my plants in pots, hauling in 6-7 yards of good topsoil and
replanting so the new soil will be on top of the clay and I wont have to dig
into it. I know I'm risking losing stuff, but if I just dump new soil
around my new plants, it wont alleviate the promplem of them having to
emerge THROUGH the clay again next year. Make sense? Or is this a huge bad
idea? When would be the best time?
Plants I can remember off the top of my head:
Lily-of-the-valley
Peony
buttercup
asiatic/oriental lilies
mallows
lithrum
rudbeckia
shasta and crazy daisies
chameleon plant
dianthus
potentilla
veronica
salvia
hostas
vareigated sweet flag
astilbes
bee balm
gooseneck loosestrife
japanese blood grass
gayfeather
daylilies
I'm forgetting some, but that's the idea of what I have to dig up.
Thanks!


Curious....

two things, one is the lake keeping temps down, and the other is that
clay warms more slowly than other types of soils. Then, of course,
there is the amount of sunlight they get (full sun is good), whether or
not they are near a wall (wall is good) or at the bottom of a slope
(bottom is bad). if you mulch before the soil has warmed up, that is a
major difference. On the other hand, your plants probably last longer
in the fall.

The only thing you can really do to help them is make sure you mulch
after june 15. you can of course dig them all up in october and replant
them in a raised bed. Most of them will not mind it. That will speed
their emergence by a lot because a raised bed warms much faster.