The use of indicator plants in Permaculture is well documented, but like any 'pattern', we can use the same basic idea for other purposes. As my primary focus is beekeeping, I'll use mainly beekeeping examples.

Forage Availability

I plant Tagetes tenuifolia (Lemon Gem) as a companion plant in my vegetable beds. It's a type of marigold, with edible flowers, and it flowers all Summer. Despite attracting hordes of hoverflies, and small wasps, the honeybees tend to leave it alone. It probably has quite a low concentration of nectar. I handweed, which means that these flowers are at head height in my raised beds, and so it becomes very obvious when the honeybees start to collect nectar from the Lemon Gems, as they are flying around my face. This only occurs when the hives are unable to find decent sources of nectar, and tells me that I have to watch out for robbing at the hives, and potentially think about providing supplementary feeding. In the long term, it helps me to identify when the gaps in the local forage occur, and to start researching suitable forage plants, and growing them.

Buddleia davidii is the same. Normally ignored by honeybees, but worked when other sources of nectar are in short supply.

As a matter of interest, I've also noticed that the main infestations of cabbage white butterflies occur just as the Buddleia is coming into flower, and that it's time to put out my netting.

Preferred Forage

The closest town has a few beekeepers, with lots of gardens, and a couple of garden centres, providing forage. Despite this, whenever the Purple Loosestrife (Lythrum salicaria) is in bloom near the river, it is always covered in honeybees. I cannot be sure exactly what the attraction is. It might be that it has a high nectar concentration, or perhaps that the plants have a better source of minerals from the water, but it is clear that it is an attractive source of forage, so I am growing some in my swales.

Last year it became clear that there was a shortage of forage late Summer. There is normally a decent supply of clover, but it was cut early in the season, and then the temperature never really got high enough (20-22  C) for the white clover to produce nectar. A visit to a small nursery, within flying range of somebody else's bees, identified Eupatorium as a good source of nectar, along with Helianthus 'lemon queen'. I bought some plants to divide this Spring, and also ordered seed, to produce larger quantities.

Timing

People often open hives too early in the season. Old beekeeping lore, here in the UK, says that you shouldn't open hives until you have a warm mild day, and the flowering currant (Ribes sanguineum) is in bloom.

These are just some of the things that I have noticed. Some will be climate specific, and not all of you will be beekeepers, but the principle is the same.

Observe. Ask why something that you've seen is happenning? Why something that normally happens, is not? Why something that you've never seen happen, has?

The rewards are not just the knowledge that it brings. Not only can this lead to new research and discoveries, but you get to see so much more.

Take Care

Deano