Spiky Plant...Yucca? What is causing brown leaves?

christian.morton

I've got this plant in my garden...is it Yucca?

Any idea what might be causing the leaves to brown like they are? They look unhealthy rather than browning through age (which I read would occur at the bottom of the plant).

Slow-worm

Are the brown bits crispy or soft?
If they're crispy it could be underwatering, if they're soft too much water. I don't know about potential diseases. 

Posy

You do get damage to leaves, especially in suddenly harsh conditions such as cold winds or frost. Is the damage worse than most years? Your plant looks very overcrowded, too, which it won't like. If it were mine, I'd cut out the obviously dead bits, thin it a little and cut back the surrounding shrubs to give it more space and air.