Question
We removed a very mature hedge of myoporum (trunks 4-5 inches)by cutting to the ground. We then planted 5 gallon Oleander in the spaces between the old myoporum. The roots of the myoporum are still there of course. The oleander has been in the ground about one year. They have bloomed 3-4 times but have not grown up or out, about same size as when planted. We live in So. Calif. Could growth of the oleander be impeded by the old myoporum roots? Are they not compatible near to each other? Thanks. P.S. I am one of the "legal experts" and using this service myself for the first time. Glenn in Santa Barbara

Answer
Hi Glenn, Myoporum is toxic to animals, but I've never seen any reference to the toxins inhibiting plant growth.  How do the oleanders look?  If they still appear healthy after this much time, I'd increase the amount and frequency of your fertilizer.  Many times, plants spend the first growing season developing roots, with little top growth.  If they aren't healthy looking, check you pH.  Myoporum tolerate alkaline soils better than oleanders.  I'd like the pH to be 6-6.5 for oleanders.  You may need to dig one up to see how much outward root development you're getting.  Myoporum have extensive root systems and often form monocultures by choking out the competition.  You may need to do some soil aeration and/or renovation so the oleanders have some space of their own.  Try to dig near the old trunks.  If you can push a shovel into the soil, then the roots aren't the problem.  
If you dig one up and the roots are encircling the rootball, then you need to dig a much wider hole, loosen the soil, and then replant.
Check for live roots at the bottom of the rootball.  Blackened roots would indicate a drainage problem.
Oleanders and tough plants.  I'd probably start by spray feeding them, soil and foliage, with a water soluble fertilizer and see if that makes them jump.  Jim