Hi Kirsty. You've asked this question twice before - last time Bamboo asked for more information, but you haven't given most of it. As more than one plant is known as "arum lily" she asked if you mean the one with the Latin name, Zantedeschia, and is it in a pot or the ground?

We now know that you planted it in April.

You say you've been told that arum lilies like water-logged soil and yours is dusty - so it looks as though you've answered the question yourself. Feeding a plant that's dried out won't make any difference, it can't absorb it. People and plants can last much longer without food than they can without water. Water is the second priority, after air.

If your soil is full of rubble you could remove some or as much as you can, or you could add compost (home made and / or bought) to it. I find adding a bit of the water-retaining gel they sell for container planting to the planting hole when I'm putting plants in the ground helps to make the soil hold moiture a bit better, but it doesn't add any nutrients.

And if no-one replies to your question, sorry, but it's because no-one knows the answer.

The compost can be laid on top, and that alone will help the soil stay moister, though a little help with a hosepipe may be in order too. Once the water problem is solved, a little plant food will probably help it to recover faster, though it is late enough to go easy on nitrogen. For Zantedeschias, I prefer fertilizers with a high potash content--the last number on the label--so I would add some seaweed meal or greensand to what you have already put on there.

thanks to you for your help and advice............ I will see
what happens in the next few months. Thanks again