I have been advised to use white oil insecticide on my Grevillias for black scale and other pests. It won't harm the bush, will it?
Just make sure that you do not use it in bright light. White oil can occasionally burn a plant on a very sunny day. You may also want to look into neem oil. It is effective on these pests and safe for people and pets and will not intensify sunlight. Here is more info: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
I have just been pruning under a large Grevillea, as its lower branches were laying on the ground. I have come across two very large spotted garden slugs - Limax maxumus. I have found one other one about 12 months ago. Can you tell me how to get rid of them please?
Here is a link to an article that should help you out: https://www.gardeningknowhow.com/plant-problems/pests/facts-about-slugs-and-how-to-kill-garden-slugs.htm
I have a 3yr old Grevillea 'Long John' in the ground. It is thriving and looks beautifully alive. But for the last 3 months or so the foliage is turning from a dark green to yellow. I had been watering it twice a week for 8 minutes and when I noticed it getting lighter I changed it to 8 minutes once a week. It did not seem to make any difference, it is now almost yellow. But it still looks absolutely blooming. WHY IS THIS PLANT TURNING YELLOW?
This sounds like a pH issue. Is this close to any water outlets, or maybe the street? It appears to be experiencing some pH swings. I would recommend applying dolomitic lime to the area around the tree. Here is a link to some articles that will help: https://www.gardeningknowhow.com/houseplants/grevillea/
Very new at this game. wishing to try my luck at grafting
As long as you graft from the same genus, then it is possible.
Here are some articles that will help:
It is a pine like evergreen small shrub covered in red flowers at the moment. Thanks
It appears to be a Grevillea.