Summer hydration

At the risk of sounding like a complete geek – oh, I forgot, I am a complete geek – I want to talk about summer hydration. In some of my horticulture talks I discuss summer irrigation. The tip given is to water deeply a couple of times during the summer to keep plants – and I’m talking about coastal sage scrub plants that are established – looking a bit greener, and the garden a bit lusher. Some of the common garden natives that benefit from this practice are monkey flowers (Mimulus aurantiacus), sages including some cultivars, black, purple and Cleveland sage, and even some of the California lilacs (Ceanothus). Hot, inland gardens with coastal plants also benefit from a few soakings during the summer. Some plants, such as flannel bush (Fremontodendron), many bulbs, and wooly blue curls (Trichostoma lanatum), are especially susceptible to soil pathogens that become active in hot, moist soils, and should not receive summer water at all.The following is a picture essay of how sages in my garden have responded to a deep, mid-summer soaking. I hope that you can see the change that occurs in the plants. I tend to be very stingy with water, especially in the sidewalk garden. I could have kept the plants looking better had I irrigated a bit earlier in the season. It should be noted, though, that keeping some of these plants hydrated during the summer comes at a cost, they may not live as long as they would have had they been allowed to go summer dormant. This does not apply to all native sages since some come from areas with more coastal fog and they require additional summer moisture in inland areas with little marine influence. As with everything, it just takes getting to know your plants to figure out what they want most.

White sage (Salvia apiana, left front) does not need any summer irrigation. Behind it is a Mrs. Beard sage (Salvia ‘Mrs. Beard’) that has gone quite dry. (June 19, 2012)

This area receives occasional water for the non-native and stupidly-selected Chinese fringe trees. A soaker hose below the mulch soaks the area about once a month. I ran the  water for several hours on July 7th, before leaving for vacation.  (July 29, 2012)

Young Winnifred Gilman Cleveland sage (Salvia clevelandii ‘Winnifred Gilman’) is quite parched. (July 29, 2012)

One day after a good soaking it looks much more verdant – for a gray-green sage, that is. (Aug. 1, 2012)

Close-up of Winnifred Gilman leaves before water. Notice that it does not go completely dormant. Larger, older leaves turn yellow and die while young leaves at the nodes are small but still lush. This is also true of sticky monkey flowers (Mimulus aurantiacus and cultivars). I find it best not to let these plants go completely dry. If anyone has any other information on how dry is too dry, please comment! (July 29, 2012)

Winnifred after a shower. (Aug. 1, 2012)

Emerald Cascade (Salvia munzii ‘Emerald Cascade’) is not exactly cascading. Too dry? (July 29, 2012)

Emerald Cascade sage one day after a soaking. (Aug. 1, 2012)

I’d love to hear from any of you native gardeners, especially those living in hot, inland areas, on how little – work, water, etc. – is enough.