Unfortunately, soaking the plant overnight has done some detrimental damage causing the plant to collapse. In most situations, no plant should be soaked in water for more than an hour unless it is a bare-rooted plant that requires deep rehydration. Like us, plants do not do well in buckets of water as they suffocate. Lavenders, in general, are fairly hardy and can bounce back from extreme situations.
We recommend tip pruning any of the flowers off the plant as this will reduce the amount of energy the plant is putting into blooming and instead will divert its energy into recovery. It could take several days or weeks for the plant to return to a normal appearance. Ensure to avoid overfeeding the plant during this time, which can also add to its stress. Ensure any hand watering is kept to a minimum; it is important for the plant to dry out. Position the plant in a sunny to part-shaded area whilst it is recovering. Once the plant produces good new growth and vigour, place it in an all-day sun position.
Our Lavinnova Lavenders are Lavandula pedunculata which are Australian-bred varieties, non-weedy and are not a stoechas form.