Alina W

Help needed........

I wouldn't rush to get rid of the trees - in such an open site they add height, structure and possibly provide some shelter from the wind.

Instead, think about what you want in the garden, e.g., types of shrub, bulb plantings, areas of perennials.

Then try planning it around what is already there - that will show you what might be best moved or altered. Work on paper first, though - much better to have a plan before you start stripping things away and find yourself with nothing more than mud to look at.

Siberian Iris

You should be fine in spring - in fact, it's so tough that I move it around at any time.

Clematis

Sorry to disagree, flowering rose, but Taylors Clematis says the exact opposite:

"Good feeding is important. In order to produce good flowers the plants should be fed by a good general, branded fertilizer following the manufacturer's recommendations- twice a week. Start feeding by mid-spring and continue until just before flowering. Do not feed during flowering as this will tend to reduce the flowering period."

See here: http://www.taylorsclematis.co.uk/plant-care.html

Rocky soil

Bark is fine. It will only affect the top layer of soil, and your roses' roots will be much deeper, so won't be affected.

Clematis

Are you feeding your plants regularly throughout the summer? Last summer, for example, was so wet that a single spring feed would have been washed out of the ground, leaving the plants very hungry.

Where for art thou sumac

Having had suckers from a tree two houses away in my front garden I'm afraid that I have to agree with Jo - it can be a real nuisance.

PLANTING NOW

Since they're only young cuttings you could keep them in pots over winter. Do lag the pots, though - even though they're hardy, they prefer not to have frozen roots.

Jelly like substance

It's unlikely to be mould or fungi - slime mould would need a compacted and very wet soil.

Most likely water-retaining gel - see if it vanishes after a few dry days. In any case, very unlikely to be anything to worry about.

Fungus?

Have a look at my answer to this question here, too, for more treatment details.

PLANTING NOW

Definitely plant them now - there's no point to keeping them in pots. Clematis should be planted about 6" (15cm) deeper than it is in the pot.