Linneaz

The plant size is difficult to ascertain from your photo, but the habit of the plant suggests the weed called bedstraw or perhaps cleaver weed if it is quite tiny. Does it have a square stem, and stick to your clothing?

Although the blossom resembles euphorbia, I believe this is actually miner's lettuce, an edible native.

Check out the various ligularias. Quite a few have leaves in that shape, and they tend to be very large. There are several bloom forms, so identification may depend on how yours looks when in full bloom.

Might it be Viola hederacea - Native or Ivy-leaf Violet?

They would appear to be tulip tree (liriodendron tulipifera) seeds.

It is a euphorbia, (Euphorbia characias subsp. wulfenii most likely) and ideally, would be upright and bushy. The easiest way to get a better plant would be to allow it to flower and then set seed. They tend to be quite prolific, and you can then harvest the seedlings for some new plants. Beware though that euphorbia is poisonous (like its family member poinsettia). The sap may irritate skin and eyes.

I am afraid it is probably giant hogweed (Heracleum mantegazzianum), a very dangerous plant. Even a tiny amount of the sap can cause painful burns and blisters if you get any on your skin, and that area is then exposed to sunlight. Check on the internet for images to compare, then check your area noxious plant regulations. It can be a huge financial liability to have these plants anywhere that children might be harmed by them.

Ceratostigma plumbaginoides, AKA plumbago. A nice plant for off-season flowering.

It would appear to be a Japanese knotweed, AKA polygonum cuspidatum or Fallopia japonica, an invasive weed or valuable herb, depending on your perspective. If knotweed, it will grow tall and have white blossoms.

Alternatively, it could be ceratostigma plumbaginoides, a groundcover perennial with blue blossoms in the fall.

Both have very similar alternate leaves with fleshy stems.

It would appear to be spurge laurel, an escapee from English gardens. Properly known as Daphne laureola subsp. laureola. Although picturesque, it is considered a dangerous invader as all parts of it are very poisonous.

Clematis alpina. Mine is a darker blue, so I am not sure exactly which cultivar you have.

Looks like a hellebore, probably foetidus, the stinking hellebore. You will need to look for flowers in late winter, early spring.

I don't know about your hand notation, but the shiny opposite leaves with the crinkled edge are just like those of Garrya elliptica. If it is a Garrya, it will eventually develop tassels in late winter or early spring. You are unsure if it is deciduous; the Garrya is evergreen. It is native to warm temperate regions of the west coast.

Sorry about that. What do you think about Primula sieboldii 'Snowdrop', or possibly some other species primula?

I googled it and found it. Here is the name and description from a site about restoring the native landscape (http://www.restoringthelandscape.com/2011/05/native-plant-of-week-cut-leaved.html):

Cut Leaved Toothwort ~ Cardamine concatenata (Dentaria laciniata)

Cut Leaved Toothwort is another spring woodland ephemeral that just started to flower this week here in central Minnesota. The four parted white flowers are arranged in a cluster above the whorled deeply toothed leaves.

I think you will find that it is comfrey, not borage. It is a medicinal herb, has a root as large as your forearm, and is almost impossible to eradicate. You may not want to eradicate it however, since it is terrific in the compost. An overfull compost will reduce itself to half its size overnight with a top dressing of comfrey leaves. And check out "manure tea". With comfrey as an ingredient, it is a splendid tonic for all plants.

Crown Imperial Lily. Gorgeous plant.

Haquetia epipactis. It may have a common name, but I don't know it. Mine grow in a moderately sunny spot in the Pacific Northwest. I think they are really cute.

The leaf is a good clue to the polygonum family (now known as persicaria). A google search quickly finds polygonum capitatum, AKA pink knotweed. Nancy Ondra at hayefield.com has a nice article on self-sowers that includes a write-up on this plant.

Shrimp Plant (Justicia brandegeana). Don't know which one, but that should get you looking in the right place.

Scilla peruviana
Stout stems up to 30cm bearing large conical heads of deep blue flowers from late April through till early June. Requires a rich, well drained soil in good light. Very large bulbs.

The leaves and aggressiveness suggest trumpet vine (campsis radicans). They do have beautiful orange-red flowers later in the summer, and are said to be a magnet for hummingbirds.

Looks a lot like Carpenteria californica. Are you in zone 8 or warmer?

I have these in the forested area of my garden in the Pacific Northwest. I have previously identified these in my garden, but my filing system has failed me! I think it is a member of the lily family. In the west it would be Streptopus roseus, AKA Rosy Twistedstalk. Streptopus amplexifolius looks a lot like it too, and both seem to be considered noxious weeds, but on the other hand to have edible berries. Take your choice.

How about Dwarf Golden Feverfew, AKA Golden Feather, properly known as Tanacetum parthenium 'Aureum'?

I think you have a ligularia, probably "The Rocket".

Macleaya cordata, possibly recently renamed bocconia cordata. In the poppy family, generally grown for its foliage.

Any chance of a few more hints? Zone, whether or not evergreen, shrub or vine?

I think you are looking at pink spirea, AKA hardtack, Spirea douglasii, native to wet areas in the Pacific Northwest.

I think you will find that something in the Persicaria or Fallopia group will give you a good clue. Japanese knotweed is a gorgeous and invasive plant that goes by either name, but there are lots of other family members. The leaf looks about right for this group, whereas the flowers look more like the aruncus (goat's beard) but your photo does not show a pinnate leaf.

Mountain Sandwort (Arenaria montana) might be the name you are looking for. Two to four inches high, 1 foot spread, 5-petaled 1 inch flowers in late spring.

If not the right name, perhaps a close-up of the foliage and a bit more description would help.

It looks like a Saruma henryi to me. Are you in the mild Pacific Northwest? The Saruma is a close cousin of the ginger plant, and is about 15-18 inches tall with yellow flowers. The one in my garden remained green this winter.

And the other one is a Lysimachia punctata.

The large-leaved plant is a petasites. There are several species, but probably japonica.