A weed growing throught new tarmac

Hi
I just got back of house tarmaced a month our so ago and as below pictures show where a weed had pushed through just 1, I poured a cap full of straight gallop over it will this be the end of it , I see no more on the tar and I think it's coltsfoot and we have never had colts foot in garden and we live in countryside fields beside us I have never seen it , will the gallop end this weed our should I expect more to apear our is this just a freak chance seedling, I have placed a stone were it pushed through I pulled the leafs of as I was passing and just thought it was a fallen leaf at first

 

I doubt its a seedling, more like a root that was growing there before the tarmac was laid.

 

They took away the surface stones and replaced them with that fine stone to level it then tarmaced it would it have came in on the stones do you think?

 

I doubt it, but possible I suppose.
It would really need to be an established plant to push up through the tarmac, depending on how thick it is, I would have thought.

 

We've had the same problem with a dandelion growing up through new tarmac -45cm deep over hardcore which was rammed down. It's near the edge however and I can only surmise the level might not be so deep at that point and that the dandelion root was already growing there. I've used Resolva on it which has killed the surface greenery - time till tell if the root had also been killed!

 

There was a very interesting similar segment on radio 2 only yesterday. Horror stories of bamboo sending out horizontal runners from the mother plant and sending them up, sometimes in people's living rooms!!! Nasty.

My guess is as @pete. Already an established plant underneath that was hell bent on finding the light!

 

Yes - that item reminded me of all the bamboo defenders that don't realise how big a problem it can be @Esoxlucius. I've often mentioned the man who was an expert grower of them, doing an item on G's World a long time ago, and he stated that even the clumping ones can get enormous, despite people always believing they're fine. Conditions always dictate how big something will grow.
Persistent weeds will easily find a way through any small gap in tarmac or similar. Coltsfoot can be very persistent, and can spread to become enormous areas. It's easy to think it's not present, but it can lie dormant, and often appears in disturbed ground, so it's more likely that it's appeared due to the ground being prepped for tarmac.

 

Yes, there are some nasty ones out there for sure, most, I believe, are invasive too. The Japanese Knotweed was the subject of another Radio 2 segment a few months ago. Yikes, that sucker is gnarly, lol.

The biggest nightmare I have regarding weeds are damn dandelions, lol. I think I'll take dandelions all day long after the problems I've heard other gardeners have had with other species.

 

Bear in mind that bracken and fungi can also grow through tarmac.
If you take notice of all the scare stories on Radio 2, in the papers and online then the only thing left is to dig out all the garden to say 6ft down, line with thick rubber before back filling with high quality reinforced concrete and then paint the surface green to remind yourself of grass.
You will always hear far more bad news than good.

 

It's always about common sense @NigelJ , isn't it? Unfortunately, that term is one of the most inappropriately named ones in existence! Bamboo was often touted as an easy solution to privacy along boundaries etc, and that's when it can get tricky, because people don't always realise how easily it can get out of control, and suddenly it's taken over and in all sorts of hard to access places.
Some 'invasive' plants are much easier to eradicate than others though. Brambles [blackberries] are often considered to be extremely difficult to eradicate, but they're quite easy to dig out if you get stuck in soon enough. It's all about balance, in the approach to sorting anything troublesome in a garden. Vigilance is needed.

Rhodo ponticum is a serious problem up here in our glens because it smothers everything in it's path, and affects the balance of natural planting that's vital to our wildlife. However, it isn't seen as problematic because people don't often actively plant it in their gardens as such, even though it's regularly used as a rootstock for other varieties. It can be a problem if the named variety dies though, and the rootstock takes over. I'm not sure how many people are aware of that though.

 

I think it's often down to regular maintenance when it comes to a lot of the so called invasive plants.
Lots of plants can be called invasive if left to their own devises, it only takes a non gardener and a media reporter to get together and suddenly you have a plant that is a "plague ".

 

Back when we had new concrete motorways/roads some bulker drivers wouldn't clean their trailars after doing wheat then pick up a load of stone for a concrete plant, the stone then went to be made into concrete and out for a motorways a few days/weeks later wheat was growing out of the concrete and some bits had to be ripped out and redone

 

It is genetically impossible for a truly clumping bamboo (pachymorph) to become invasive. These articles explains why:

Clumping vs Running Bamboos - Bamboo Sourcery Nursery & Gardens

Bamboo Morphology | Bamboo Info

 

But the mature size of the clump could easily extend to the other side of a fence or wall, if it's planted fairly close and no root barrier used. That's invasive from the point of view of the other side.