Can I grow a Quince tree together intertwined with a Magnolia and expect them both to thrive?
I wouldn’t, as your objective is to get them both to ‘thrive’. They are both deciduous and need to make best use of the available light during summer. Lower light levels will potentially cause them to become weaker and probably flower less, which would be a pity as they are both beautiful trees/shrubs. You don’t mention which magnolia variety you’re thinking of – some of them can grow very tall and would dwarf the Quince. If you want them to complement each other, try planting them nearby, avoiding the taller Magnolia shading the Quince too much. You could consider some evergreen plant(s) which would add winter interest too. Remember, these plants can live for decades and their root systems will expand, alongside their above ground growth -greater competition for nutrients and water too. Good luck!
