Stroll through any corner of San Diego County on a warm spring day, and you’ll likely encounter a potent cocktail of intoxicating scents no matter where you go. The relatively unsung olfactory experience of the county’s open spaces often proves to be the chief pleasure on many hikes, with hundreds of different plants releasing their essential oils into the air.

This blog examines the types of plants you are likely to encounter in all four of the general regions of the county, including the Coast, Foothills, Mountains, and Deserts. I’ve found the olfactory experience of San Diego to be an essential part of hiking. It’s my hope that this informal guide will help you to identify the plants that smell so good while also deepening your experience.

Shrubs

Sages

Sages are an aromatic shrub or herb in the mint family that show up across the county in a variety of terrains. In some locations, sages are the dominant plant species, and when conditions are right, the smell can be overpowering. Sages are a common plant in Mediterranean climates, characterized by warm, dry summers and mild, wet winters.

Black Sage

One of the most common forms of sage that occurs generally within the coastal sagebrush communities. It sometimes intermixes into the chaparral communities, but usually stays within 20-30 miles from the coast. The leaves of this sage are a dark green, and the stems are even darker. Pure stands of black sage often appear so dark that they take on an almost black color. The slopes of Black Mountain in Rancho Penasquitos are covered in many thickets of sage, which gives the mountain a dark look in comparison to the lighter grasslands surrounding it.

White Sage

More widespread and therefore more common that black sage, white sage occurs from the coastal areas all the way to the desert. It tolerates warm, sunny hillsides, but may also occur interspersed in chaparral, oak woodlands, and desert slopes. The color of the leaves is actually a pale mint green, which makes it stand out more from surrounding plant communities than other sages. The flower stalks of this sage are very long, and the flowers can be powerfully aromatic, especially on warm days.

Cleveland Sage:

Much less common than black sage and white sage, Cleveland sage is more prevalent in the southern third of the county. The smell is probably the most potent and intoxicating of the sages, and even if you can’t recognize it by sight, you won’t fail to notice the scent when you walk past. There are some great patches of it on Sycuan Peak and McGinty Mountain. It has a light green color similar to white sage, but the leaves are much smaller than both white sage and black sage.

Desert Sage

Desert sage looks very similar to white sage, although it seldom grows as large both in stature and in the size of its leaves. You’re most likely to see white sage interspersed in cactus scrub belts where other common species include agave, cholla, desert apricot, barrel cactus, mammalaria, creosote, and, on occasion where transitions occur, California juniper. The scent is more subtle, but similar to white sage. Lucky hikers who catch a whiff of it on desert slopes may have been the beneficiary of Kumeyaay blessings.

Sagebrush

Sagebrush, despite the similarity in name, is unrelated to the true sages, although Great Basin Sagebrush maintains some superficial resemblance. The fragrances are similarly redolent, but more perfumed and sweeter, without the pungency of true sages.

Coastal Sagebrush

This is the more common of the two sagebrushes, and it occurs everywhere from the coast to the bases of the Peninsular Ranges. Its mint-green leaves are small, soft, and thin, almost like filaments. It’s scent is one of the sweetest of all the plants in San Diego County. If you take a few leaves and roll them in your hands, you’ll be awash in a wonderfully bright fragrance.

Great Basin Sagebrush

This sagebrush is more common in the interior and in various places in the mountains, where it co-occurs with oak woodlands and chaparral. I’ve seen a fair amount of it in McCain Valley, Warner Springs, and around Lake Morena/Boulder Oaks, but it pops up here and there in other locales. The scent is not quite as sweet or powerful as coastal sagebrush, but it is distinctive. This plant is also popularly known as “Cowboy Cologne.”

Miscellaneous

Yerba Santa and Poodle Dog Bush

The “sacred herb” grows in a number of locations along the coast and in the foothills. The silver-green, ridged leaves of this plant emit a scent similar to sage, but slightly more subtle. You’ll get a better feel for the smell by crushing the soft, velvety, almost semi-succulent leaves in your hand. The flowers of the plant also emit a similar, albeit more distinct scent.

Poodle dog bush is closely related to yerba santa, which is a fire following shrub that produces a similar, but far less pleasant aroma that’s actually closer to a skunk or marijuana. Yerba santa won’t harm you, but poodle dog bush most certainly will. Poodle dog bush contains skin irritants the cause a nasty skin rash that is said to be much worse than poison oak.

 

Ceanothus (Lilac)

Although they are unassuming and fairly indistinct members of the chaparral community for about 9 months out of the year, ceanothus explodes with color and fragrance during late winter and early spring. The bright blue or white clusters of ceanothus blossoms can take over entire hillsides, adding vivid splashes of blue to contrast against the more uniform greens of the chaparral and the brighter greens of winter grass.

Lakeside Lilac

Known by the name Lakeside due to its common location, this species of ceanothus grows from Ramona to Dehesa between 500′-4000′. The flowers on this variety of lilac are particularly distinct. Instead of the pale blues and whites characteristic of other lilacs, this variety is generally a darker, deeper blue.

Chaparral Whitethorn

One of the most abundant and distinctive of the ceanothus species, Whitethorn is common in the chaparral and foothills of local mountains. The flowers are blue, ranging from pale to sky-blue, and when in full bloom, this plant adds vivid splashes of blue across hillsides. Oak Canyon is a great place to see chaparral whitethorn; during March of wet years, the canyon’s western wall is plastered with brilliant blue suffusing the air with a rich, honeyed scent.

Hoary-Leaf Ceanothus

Another common ceanothus variety, hoary-leaf ceanothus grows in many of the same places as chaparral whitethorn, although it is especially common in Poway near Iron Mountain and Ellie Lane, as well as on the drier sides of some of the Peninsular Ranges. The scent from the flower is similar to that of whitethorn, although the shape and color of the flower are very different. This ceanothus produces white petals and larger individual flowers.

Ribbonwood

This member of chaparral communities occasionally reaches tree height, but it is still generally associated with shrubs. The plant has a reddish, perpetually peeling bark with light green, feathery foliage. Unlike most chaparral plants, ribbonwood exudes a subtle, but sweet fragrance. It’s not as potent as the lilac blossoms or sages, but the fragrance is still a welcome addition to the otherwise scentless montane chaparral communities.

Wild Fennel

This invasive species hitched its way across the Atlantic from the Mediterranean where it found a climate very much to its liking. It’s rare to see fennel outside of the coast, but in some places like Penasquitos Canyon, fennel is pretty common. It grows in thin, green stalks with yellow flowers. The foliage is feathery and light. Snap one of the stalks, and fennel will exude its characteristic licorice smell. During the summer when the seeds dry out, you can eat the fennel seeds for a powerfully sweet licorice flavor.

Creosote

The ubiquitous desert species generally flies under the radar despite being nearly everywhere. It thrives best in the vast desert flatlands, but also shows up on rocky slopes across a variety of desert communities. Most of the time, the plant is unremarkable, despite the fact that it can reproduce by cloning. There may be specimens that have survived by cloning for 10,000 years or more. However, when rare rains soak the desert soil, the overwhelming scent of creosote is unmistakable and intoxicating. To get a small dose of that scent on dry days, pick a few creosote leaves and crush them in your fingers to get a fraction of the effect.

Desert Lavender

This common shrub appears most often in desert washes and canyons. It’s a favored plant of honeybees in the area given its rich aromatic smell that often graces the air during late winter. The scent is similar to true lavender, but more spiced and less floral.

Desert Apricot

Actually a species of the rose family (trust me; I’ve felt the thorns) and not actually a stone fruit, this shrub occurs commonly in the middle elevations of the desert, often alongside California juniper. The flowers of the plant emit a scent highly reminiscent of ceanothus – sweet and honeyed. The fruits on the plant are yellow and egg-shaped – hence the name, and they were an important part of the Cahuilla diet.

Western Azalea

Western azalea, like ceanothus, is another unassuming shrub that shows its true colors during the spring months. This mountain species is extremely rare in arid San Diego. You can find it in Palomar State Park near the Weir, along the Cedar Trail, and along the Chimney Flat Trail. You can find it in Cuyamaca Rancho State Park along the Azalea Glen Trail. When the plant is in bloom, its blossoms exude a sweet, perfume-like scent.

Southern Mountain Misery

This plant is a relative of a common mountain species that intermixes on the drier slopes in the Sierra Nevada. It is relatively rare here in San Diego, with the largest patches growing on Otay Mountain. The plants blossoms resemble strawberry blossoms. The smell is unusual, and it’s said to resemble witchhazel. I don’t really have a better analog for it, but the smell is sweet, and memorable.

 

Trees

Jeffrey Pine

All of San Diego’s pines, which include Torrey, Coulter, Jeffrey, pinyon, ponderosa, knobcone, and sugar pines, feature some kind of distinctive pine smell, but it is the Jeffrey pine that stands out in particular. This pine is most common in the Laguna Mountains, where it forms large forests along the edges of Laguna Meadow and intermixes with black oaks. The scent of the local pines aren’t nearly as powerful as those in the Sierra, as drought tends to diminish the scent. When you find a tree with a strong scent, it will remind you of butterscotch, vanilla, or cake. Press your nose deep into the grooves in the bark and inhale deeply. This may be one of the loveliest scents in the entire county.

Incense Cedar

Incense cedar was sometimes used in the construction of cedar chests, which have a reputation for repelling insects. Most plants exude scents (flowers excluded) to repel pests, and incense cedars woody, spicy scent protects it from a variety of pests. Incense cedar is most common in the Palomar Mountains, although you’ll also find it in the Laguna Mountains, Cuyamaca Mountains, on Hot Spring Mountain, and in the Volcan Mountains. The smell is strongest on warm fall days.

California Juniper

Although it usually resembles a bush, this plant is actually a conifer given that it produces cones, commonly referred to as berries. It is a cousin of incense cedar and, believe it or not, giant sequoias and redwoods. Junipers produce a smell similar to, but stronger than incense cedar, especially on warm days. The plant is a signature species of the high desert, and you’ll find it most often above 4,000′ in the desert, co-occurring with pinyon pines. Junipers sometimes grow as low as 2500′ on protected, north-facing slopes.

California Bay Laurel

Also known as the pepperwood due to its reputation for producing violent headaches and sneezing fits when people inhale its fragrance too deeply. This is one of the most powerful scents of any plant in San Diego, let alone California. It is very common from the Transverse Ranges in Los Angeles and Ventura Counties north, but relatively rare in San Diego. You can find sporadic patches in the Laguna Mountains and In-Ko-Pah Mountains. The easiest place to spot them is on the Pepperwood Trail in McCain Valley. You can roast and eat the nuts, which are said to contain a pretty powerful stimulant. The flavor is similar to coffee.

Peruvian Pepper Tree

Another export, this time from Peru. The Peruvian pepper tree loves the California climate so much and has become such an essential part of SoCal’s urban forest that many people mistake it for a local species. It doesn’t show up a lot on hikes since it’s a planted species, but you will see it occasionally in places that once functioned as ranches, including Penasquitos Canyon and Daley Ranch. The smell is less potent than other trees, but still distinctive.

Eucalyptus

Yet another export that has thrived so successfully that many people still assume it’s a local plant. Eucalypts were imported from Australia to create an urban forest in the otherwise scrubby coastal regions of California. Loved and reviled by many as both a signature tree for the state and an invasive pest, the trees primary value aside from windbreaks and ornamental purposes comes from its popular essential oils. The plant releases those essential oils into the air when you crush the leaves or when the weather is warm. You can find it nearly anywhere in coastal San Diego, although Batiquitos Lagoon and Hosp Grove, both in Carlsbad, have fairly impressive groves.

Note: I used James Lightner’s excellent San Diego County Native Plants as a reference for this blog post. For anybody interested in the botany of the county, this book is a must have.