I see too many ponds surrounded only by a naked border of stone. While a mix of boulders, smaller stones, and river washed gravel can be arranged to mimic the edge of a mountain stream, without plants the pond looks sterile and man-made.
I have planted along the borders of the garden’s five ponds so that hostas and Japanese Forest grass arch over moss covered stones (above). Variegated and golden sweetflags (Acorus gramineus), variegated cattail, and several types of rushes and iris grow in gravel in the shallows of the sunny swimming pond, providing cover for the fish and frogs and softening the look of the large granite boulders (below).
Beginning with variegated Yellow Flag iris (Iris pseudoacorus ‘Variegata’, above) in mid May, one iris or another is blooming in the swimming pond until late in June. Yellow flag must be contained so that it does not escape into the wild, and I have taken care to observe the neighboring creek and farm ponds. The seed is carried by water, not by birds, so it has been easily contained within the pond.
The variegated form is the first Japanese iris to flower in the swimming pond (Iris ensata ‘Variegata’, above), and within a week it is followed by the marvelous blooms of ‘Lion King’ (I. ensata ‘Lion King’, below). Each variety flowers for a few weeks, and with several varieties there will be blooms for a month or longer.
Japanese iris are more restrained in their growth than yellow flag, though the clumps steadily increase in size planted in shallow water. Planted in damp soil from a trickling spring, Japanese iris are a bit slower, and I’ve seen them planted in drier garden soil where I expect they are considerably less vigorous.
Today there are several Japanese iris that I’ve planted in the swimming pond, and a handful of seedlings (above), only one of which has bloomed thus far. Below, you will see a few of the varieties, and certainly I have not seen one that I would not add along the sunny edge of the ponds if I could manage to find the space.