Plant of the Month (May) : Seaside Alumroot – Heuchera pilosissima ~ Tk-123456

Seaside alumroot (Heuchera pilosissima): Mother Nature's Backyard

Garden
shade can be both a joy and a challenge.
Fortunately, Californians are blessed with plenty of charming native perennials
that are shade-lovers. Among the shady favorites
are the Heucheras (Alumroots or Coral bells).
A good example, the Seaside alumroot, is blooming right now in Mother
Nature’s Backyard.

The
genus name, given by none other than Linnaeus, honors Johann Heinrich von
Heucher, professor of Medicine and Botany at Wittenberg University.[1] The scientific name is pronounced several
ways: HOY-ker-uh, HEW-ker-uh, or
HER-ker-uh. The first pronunciation is probably closest to the original,
but all are acceptable. The species
name is pie-low-SISS-ih-muh.

The
Heucheras are delicate-appearing perennials that are hardier than they
appear. All species in the genus are
native to N. America, with thirteen native to California.[2] Some California Heucheras grow along the
coast, while others are endemic to the mountains – often with limited
geographic ranges. Only three are native to Los Angeles County: Heuchera abramsii, H. caespitosa and H. rubescens (all mountain species). Fortunately, species from
other California regions adapt well to local gardens. Heuchera
pilosissima is native to the coastal forests of Central and Northern
California (below 1000 ft. elevation).

Gardeners
around the world are familiar with Heucheras.
They’ve been grown in gardens for many years, and numerous named
cultivars are readily available.
Many cultivars derived from Heuchera americana (native to Central
and Eastern N. America) have brightly colored leaves, making them prized accent
plants in shade gardens.

Seaside alumroot (Heuchera pilosissima): foliage

The
California natives all have green leaves, though some of the mountain species
are very petite in size. Our natives
have flower colors which range from white or cream to medium pink. The darker pink and red flowers are found on
species from the American Southwest and Baja California. The Southwestern species are sometimes
crossed with California natives to produce showy hybrid cultivars.

Seaside alumroot (Heuchera pilosissima): plant

Seaside
alumroot is medium-size for California species, growing 1-2 ft. (to 0.6 m.)
tall and wide. Plants form an evergreen
mound about 1 ft. tall & wide – typical of the Heucheras. The leaves have a long petiole and are somewhat
succulent. Their shape is rounded and
looks a bit like a grape leaf. The leaf
color is bright to medium green; on our plants, the color is slightly
mottled. This species is hairier than
some native Heucheras, with the entire plant covered in shaggy white
hairs. In fact, the name pilosissima means ‘hairiest’.

Seaside alumroot (Heuchera pilosissima): flower stalk

Like
all Heucheras, Seaside alumroot produces small, bell-shaped flowers along
vertical flowering stalks. The entire
flowering stalk and flowers are covered with glandular hairs and the flowers
are densely clustered about the stalk (more so than in many species). The many flowers, and their unusual pastel
colors, make this a prize Huechera in our estimation.

The
flowers are small (0.25 inch or less) and pink or white colored (ours have a mostly
pink floral cup (hypanthium) with white tips to the petals - see photo below). The sexual parts are exserted (protrude out
from the neck of the floral cup).
Heucheras are primarily pollinated by bees. In our garden, they are visited regularly by
hummingbirds, which may also serve as pollinators.

Seaside alumroot (Heuchera pilosissima): close-up of flowers

In
general, Heucheras are not self-fertile, so you’ll need several plants if you
want seeds. We raised our Seaside
alumroot from seed. It wasn’t difficult,
the only challenge being to keep seedlings moist in our dry climate. We hope our plants will self-seed and fill in
shady areas in our garden. Heucheras
also reproduce vegetatively, producing offsets (new little plants). If plants become too large for their space
(or about every three years) they can be divided. For details on dividing Heucheras see ref. 3,
below.

In
S. California, the Alumroots do best in shade – afternoon shade to bright shade
under trees for best foliage and flowers.
Seaside alumroot does great on the north side of a wall or
building. It tolerates sandy soils and
likes a well-drained soil. That being
said, this species is doing well in our clay loam. The quoted pH is slightly acidic (pH
5.0-7.0), although ours is a bit more alkali.

Hailing
from the northern coast, Heuchera
pilosissima is adapted to more yearly precipitation than it gets in S.
California. We water our plants on the
same schedule as our apple tree – a good soak every 2-3 weeks from May through
mid-September. It could probably take
weekly water in sandy soils. The only
precaution is to not overwater in hot, humid conditions (which promote soil
fungi and root rot). Southern California
gardens are generally so dry and breezy that this is seldom a problem here.

Heucheras
are mostly disease-free and easy to manage.
Remove old leaves as needed. Cut
back flowering stalks after collecting seeds.
And divide older plants as needed.
Plants grown in containers need a dose or two of half-strength
fertilizer in late-winter or early spring (when plants begin to grow). That’s really about all.

Seaside alumroot (Heuchera pilosissima): in shady spot

in garden with Carex pansa, Ribes viburnifolium.

We
love the look of Heucheras as a ground cover in shady places. Their small size and neat appearance make
them good candidates for lining shady walkways – or growing in containers. We like to plant them near seating (we love
to have hummingbirds come within arms-length).
And Seaside alumroot gives a woodsy look to any shady garden spot.

If
you can’t find this species (plant or seed), consider the hybrid cultivar ‘Lillian’s
Pink’ (a garden hybrid between Heuchera
pilosissima and H. sanguinea). It’s readily available and has the nice
foliage characteristics of Seaside alumroot with the darker pink flowers of the
Coralbells (H. sanguinea). Any way you choose – straight species or
cultivar – California’s Heucheras are guaranteed to please!