You can always find a reason to not use something...but seeing as how the experts recommend it and use it, RoundUp is the most effective way of dealing with crop-ups. Burying them in soil will do nothing except encourage root development to proceed further. Smothering roots can cause problems with trees, but doesn't kill advancing roots. You don't say Toronto what the saplings are from...you evidently have a tree--possibly one that's been chopped down....maybe dug up...and it is sending out roots where saplings keep popping up. The constant mowing, removing and spraying RoundUp will do the job.....eventually. You might trace back to where the tree was, dig there and spray RoundUp there also. Now in the Toronto area, you may not find such herbicide on the store shelves....you might have to go wider afield...out into the suburbs. Any Canadian Tire store has it. If you plan on maybe using a weed killer ....such as Killex...it would prove time saving to buy it IN BULK...at the same time...you cant find it on shelves in Toronto proper.

"... or do I really need to hire a landscape designer?" "Design" is the thinking through portion of making a landscape. A landscape designer/landscape architect is the generalist that has the ability to visualize possibilities and lay the groundwork for making them happen. A "landscaper/excavator" would have the muscle to do the work ... but it would be absolutely "hit or miss," (depending on the skills that they've acquired outside of the typical) that they could create work that takes into account all the other aspects of a finished space. They may have not an iota of design skill more than yourself, Caitlan. In general, I find that subcontractors tend to focus strictly on their particular aspect of the job and ignore most, if not all other things. If such a person is "in charge of" design (when they really don't have the training or experience for it), they can make a complete disaster of a finished space. It is not much of a savings to to save a small percentage of the total job cost only to end up with a project one has a lot of misgivings about. Determine your true budget right up front. It will determine how far you can go and what you can do. If the budget is not adequate for professional assistance, your options are to DIY or cut aspects of the project. You can even DIY design but it requires legwork, learning and sifting through advice in order to separate out what is useful from what is not.

The TV show Fixer Upper did a house that looked similar to yours. The episode referred to the house as the "Prickly Pear" house. Link: https://magnolia.com/our-show/episode-11-the-prickly-pear-house/ They removed the bushes and trees blocking the house (& the prickly pear cactus near the street) and created dormers & a pergola in front -where your red trees are touching the roof)-Also- they installed 2sets of French doors to the front of the house and removed wall in the kitchen.

Good to see you back, Campanula. Your garden sounds like Piacenza this time of year: ratty, dry, mildewed, overgrown. Somehow it turns back into a marvel every spring. Like everybody else, it seems, I'm behind in my gardening. Last December's ice storm in particular has cost a lot of maintenance hours, and is still operating. The storm smashed all the black locusts, which took days to cut up and distribute, and now the damaged trees are suckering with determination, clearing them making another chore. 2017 was also our great Drought Year, running from fall 2016 to fall 2017. The good news there is that established plants suffered very little, taking month after month of litte to no water in their stride. We were about at the epicenter of the drought, so it was a good test situation. Deer, fairly recent arrivals, are horrible here, too: we have to protect trees, shrubs, and roses if we don't want them to be eaten or smashed. We apparently have a wolf population developing, too, and even my conservative dairy farmer neighbor suggested that perhaps wolves aren't such a bad thing for keeping the wild boars and deer under control. I want lynxes to make their way into our area: they're supposed to be major deer predators. Since we came here we've seen the wolves and the roe deer come: why not lynxes, too? I went back and re-read your original post: you planted R. helenae and 'Darlow's Enigma' in an allotment? Oh, my. Well, if you want more huge ramblers for your woods, let me recommend 'Treasure Trove', R. longicuspis, 'Brenda Colvin', and all the Ayrshires, which seem to be badly confused in commerce but are all good. I get the health and energy problems, and hope you see both restored soon. DH had a quadruple bypass and two further surgeries last year but has regained much of his previous bounce, so it can be done. I'm creaky, too, but at the moment feel okay. I'm waiting for temperatures to drop after having spent most of the last ten days flat on my back under the fan. The change may be happening as I write: it's cloudy and cooler this morning, encouraging me to think of getting out and attacking the chore of training R. longicuspis into her flowering ash, and continuing cutting back an overgrown locust and 'Treasure Trove' growing in it. Maybe, as long as I have the ladder out, I'll shear the tops of the yew hedge. The shade garden didn't even look like a garden anymore after a month or two of neglect, but DH and I have been wrestling it back into its form. I'm hopeful that the huge amount of organic matter resulting from the ice storm will make its effects felt in the coming years as it decomposes. Good luck!