Is your garden looking a little bedraggled these days with scorched foliage and crispy blooms?  No wonder, since July gave us almost two straight weeks of 100+ temperatures and August will undoubtedly have some hot days too.  If you were diligent about using mulch in your garden to cool the soil and retain moisture better, your plants may have held up pretty well to the heat.  If not, however, maybe it's time to accept the fact that we live in a Mediterranean climate and need to use plants in our gardens that are adapted to this environment. 

The speaker for our monthly Master Gardener meeting in July was Ellen Zagory, Director of Horticulture at the U.C. Davis Arboretum; her topic was particularly timely because it covered heat and drought tolerant perennials.  The following selections are very good choices for our county and if you have never toured the arboretum at Davis, now would be a great time to visit so you can see how these plants hold up in our summer heat.

Not surprisingly, lavenders top the list for heat tolerance.  One good one is Lavandula 'Goodwin Creek Grey' which has deep violet-blue flowers that appear in spring and go all the way into late fall.  It is a bit larger than most lavenders and has very dense foliage.  'Munstead' is an English lavender that has a very long bloom period, is a heat lover and makes a wonderful low hedge.  Another particularly good heat-loving lavender is one of the Spanish ones – Lavandula stoechas 'Otto Quast' which tends to be very long-lived. 

Teucrium chamaedrys or Germander is a tough plant that holds up well in hot weather.  I have this in my own garden where it gets full sun exposure all day and is flourishing with very sporadic watering; in fact, it cannot tolerate wet soil.

Origanum laevigatum 'Hopley’s' is an oregano that bears dense heads of purple-pink flowers and self-sows freely.  It's a native of Turkey, so that should speak volumes for its ability to survive our summer heat.  Another oregano that does well is the 'Betty Rollins' cultivar which spreads in a low-growing mat to make a wonderful groundcover. 

Phlomis fruticosa, commonly known as Jerusalem Sage, is another Mediterranean native that is an easy perennial shrub to grow.  It grows to about 4' tall and wide and has deep golden yellow flowers that appear in ball-shaped whorls.  This perennial looks wonderful when paired with lavenders. 

Nepeta x faassenii, or Catmint, is a low-growing, bushy perennial that can be mowed down to the ground periodically to keep it looking good.  It makes a great border or edging plant.

One of the salvias – Salvia officinalis 'Berggarten' – is a particularly good choice for hot, dry climates.  It is more compact, has denser growth and tends to be longer-lived than some of the other salvias. 

If you like ornamental grasses, Calamagrostis x acutiflora 'Karl Foerster' is a true workhorse in our hot, dry summers.  It is a sturdy, clumping-type grass with feathery, buff-colored flower plumes that persist into winter.  This grass is beautiful when mass planted.

These are but a very few examples of drought and heat tolerant perennials you can plant to keep looking good all summer long, but look at the arboretum's web site at http://arboretum.ucdavis.edu for more information.  The plants listed above are only watered every 14 days, even during the hottest periods.  However, remember that all plants, whether drought tolerant or not, must be watered fairly regularly until they are well established, usually about two growing seasons, and then you can cut back on irrigating.  July and August are not the best months for planting, but if you can't wait until the cooler days of fall, do your planting in the early morning hours when the heat is not so intense.  You will have to baby them more than if you waited until fall, but by next summer, they will have enough of a head start to perform well.