Azaleas, which are Rhododendrons, do not, in my experience, poison the soil we have over 40 in our garden and other plants and shrubs grow right up to them. Make rue your soil is acidic though you you will need to feed regularly with a ericaceous feed.

Agree with Moon growe. You can certainly grow azaleas with other plants. My hostas grow right along with my azaleas & lily of the valley. They all get along just fine.

There is ongoing research currently into the allelopathic effects of Rhododendron, but the primary subject/culprit is actually Rhododendron ponticum, the one that grows wild in the UK. Certainly there's some evidence that this particular plant may inhibit seed germination and disrupt mycorrhizal fungal activity, which assists many other plants to grow, but this allelopathic effect is not seen across all varieties of Rhododendron, including Azalea, so I wouldn't anticipate your plant will cause any problems for other plants and bulbs growing nearby.

Thanks very much for the responses, I shall go ahead without any worries now