It's the seeds which are tiny and get blown a long way in the wind which make it invasive. If you dead-head them as soon as the flowers fade you will prolong the flowering season and prevent the seeds from becoming a nuisance. Keep it and enjoy it.
The pink one on the left looks like musk mallow and is a short-lived perennial but usually grows as an annual. The purple one on the left is also a mallow, this time a pure annual so appears from self-sown seeds. The purple one on the right is purple toadflax which is another short-lived perennial but, again, usually grows as an annual and self-seeds prolifically. None of them will like being moved at this stage and will almost certainly die but may manage to form seeds before that happens.
I grow several magnolia in containers and would not use pure ericaceous compost. Add maybe 10 per cent ericaceous to a John Innes #3. They prefer slightly acidic soil but can tolerate a wide range. Pure ericaceous is just too acidic.
There is a natural 'junction' on each rose stem which allows the dead flower to detach naturally. However, a pigeon or other large bird flapping about can easily detach them at that point (the damn things are constantly chasing each other during mating rituals around my flower beds.) A stressed rose will also drop buds and flowers which will detach at the same 'junction'.
Apple trees do sometimes have small amount of blossom again if they are stressed. It's too late for fruit to form though. Young trees shouldn't be allowed to fruit until about their 3rd year anyway as they need to concentrate on putting down a decent root system. The weight of fruit can also bend or break the branches which are too young to support them.
It's certainly not Hawkweed. As previously mentioned, that only grows to about a foot high. Hawkweed also has hairy ovate leaves and orange flowers while your plant has smooth thistle-like leaves and yellow flowers. It's one of the sow thistles, maybe this one:
or if it is prickly, this one:
Last edited: 23 July 2016 11:29:02
As it has two flowerings, it is more likely a group 2 so only light pruning is needed in early spring. Follow the tips back to a pair of buds and cut just above them. If you find the flowers are getting higher each year with bare stems below then treat it as a group 3 for one year then 2 more years as a group 2. I find this is a good way to keep vigorous ones under control but still maximise flowering. You're right, there are so many clematis varieties it is often difficult to pin down the exact variety. On a rainy day, have a good browse through this site to see if you can find it:
Brassicas don't really like the loose soil in raised beds and do much better in the ground. They need firming in when planted - I use the heel of my boot and that's on clay soil. If you have no choice but to grow them in raised beds, plant them deeper (right up to the stalks of the bottom leaves) and really firm them in. Never let them go short of water.
You have a very healthy looking specimen there Flyfifer!