Hi @Ripley16,
Welcome to the Bunnings Workshop community, it is fabulous to have you with us.
Your pencil pines are struggling due to shallow roots and strong winds, but you can help them recover by encouraging deeper rooting and providing better support.
The ties you have added will work well for now, but you might consider adding long hardwood stakes to the trunk of each affected tree. This will help anchor them more evenly along the trunk and relieve pressure from the mid-trunk caused by the tree bending.
Aerating compacted soil and adding organic matter will improve soil structure and encourage deeper root growth. Use a garden fork to mix compost in with the soil at the base of the tree.
Water deeply roughly once a week to promote downward root growth. Deep watering less frequently will encourage the roots to chase the water down further into the soil, which will in turn anchor them much better than they currently are. You can also lightly mulch to retain moisture without suffocating roots.
A balanced, low-nitrogen fertiliser such as Richgro All Purpose Complete Garden Fertiliser in early Spring will also support steady growth.
With proper care, they should become more stable over time.
Allow me to tag @Noelle and @mich1972 to see what they think.
Jacob
