It is time to clean up some palms in the garden. Here is Livistona benthamii with ferns growing in the palm boots. I fear the fern will overtake the crown. Best to remove or will it be fine?
I would leave them alone but that is just me. It is a matter of what you think looks good. You can either pull them by hand or put a roundup solution on a sponge mop and climb a ladder.
I'm with Jerry. Unless you can't stand the look neither of those ferns will cause any damage, or "overtake" the crown. But I would certainly avoid any Round Up. Sponging it on up there would be a accident waiting to happen. It would be hard to hand sponge on them effectively anyway. That "sword fern" you can just grab and pull out easily if it is anything like what I have here - very few weak roots. Personally I like it. However, with a prolonged dry spell they might start looking a little ratty. Right now, I like the look. You usually only see that look in the tropics. Can you get up there anyway? How high is it?
I like the look and will leave them be. Here is another little fern called the Resurrection Fern growing on a palm trunk. Often seen growing on the limbs of the Live Oak. First pic taken in its dry state of life. The second pic taken a few hours later of same fern after a little water.
Those ferns look beautiful in a tropical rainforest sort of way. I can't imagine them ever overtaking the palm's canopy. I grow bromeliads, succulents, and staghorn ferns in/on some of my palms.
In the rainforests in my part of the state, ferns, orchids and other ephytes grow up he trunks of trees and palms naturally. Often see olderCIDP as street trees with the trunks literally covered in ferns too. To me it looks pretty, its a natural occurance and does not harm the palms. My largest Roystonea (10 metres or so) is covered by syngonium, only the crownshaft stops it from being buried, but he is big healthy palm and no damage appears to be done even by this extreme. Peachy