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| Three year old Ceanothus densiflora 'Howard McMinn' - Mother Nature's Backyard |
February is often rainy, though 2015 is thus far
the exception. One of the more pleasant
activities this time of year is admiring the early-blooming trees and
shrubs. Our ‘Ray Hartman’ Ceanothus is
usually glorious in February. And our Arctostaphylos densiflora ‘Howard
McMinn’ is a perennial favorite with humans and pollinators alike.
Vine Hill manzanita is endemic to a relatively
small area of Sonoma County, 13 miles from the Northern California coast. It grows in the Vine Hill area, between the
towns of Forestville and Sebastopol, in a part of Sonoma County best known for
its vineyards. The region is mostly
forest, with openings (‘barrens’) featuring unusual sandy clay, acidic
soils. The Vine Hill manzanita grows in
these barrens, as do several other endangered plant species: the Vine Hill ceanothus
(Ceanothus
foliosus var. vineatus) and
Vine Hill clarkia (Clarkia imbricata).
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| Specimen of Vine Hill manzanita (Arctostaphylos densiflora) Rancho Santa Ana Botanic Garden, Claremont CA |
Vine Hill manzanita was first described by Milo
Baker (Santa Rosa Junior College) in 1932, from specimens growing in what was
later to become the Vine Hill Preserve.
To learn more about the Preserve see: http://milobaker.cnps.org/index.php/conservation/preserves/vine-hill. A Pacific
Horticulture article by Philip Van Soelen provides a fascinating history of
the Preserve, the rare manzanitas associated with it, and the hybrid cultivars
arising from Arctostaphylos densiflora
(http://www.pacifichorticulture.org/articles/vine-hill-manzanita/
The species Arctostaphylos
densiflora is now limited to a small number of individuals growing in or
near the Vine Hill Preserve. It is
listed on the California Native Plant Societies Inventory of Rare and Endangered Plants as a
category 1B.1 species (rare,
threatened, or endangered in CA and elsewhere). But several cultivars of this amazing manzanita are
alive and thriving in gardens throughout California. In fact, they are some of the best known –
and garden-proven – of the California manzanitas. We are fortunate to have one in Mother
Nature’s Backyard.
The ‘Arctostaphylos
densiflora cultivars’ are likely actually hybrids between the Vine Hill
manzanita and other California Arctostaphylos
species. As discussed in the Van Soelen
article, the parentage of several common cultivars, including ‘Harmony’, ‘Howard McMinn’ and ‘Sentinel’, is
hidden in history. These cultivars arose
in the wilds or in gardens which either contained (or were within pollinator’s
flight distance) of other manzanita species.
Since manzanitas hybridize given the opportunity, our garden favorites
are likely hybrids. Only DNA studies may
someday reveal their true parentage; as far as we know, such studies have not yet
been done.
Interestingly,
the common ‘Arctostaphylos densiflora
cultivars’ share several distinctive
characteristics of their Vine Hill parent.
All have rather small (for manzanita) pinkish flowers in dense clusters
(truly ‘densiflora’). Their leaves are
almost perpendicular to the ground, giving the plants a neat, dense appearance
compared to other manzanitas. Most tend
to grow wider than tall – at least in the first several decades. And
they tolerate a wide range of soil textures from quite sandy to clay.
‘Harmony’ manzanita grows 2-4 ft tall and 4-6 ft
wide in its first decade or so; it is often used as a woody groundcover or low
foundation plant in soils ranging from sandy to clay. But it has the potential to grow to 6-7 ft.
tall and about as wide; it can be pruned up over time to reveal its attractive trunk
structure and bark. ‘Harmony’ is said to
most resemble A. densiflora; it has
larger leaves and a more open habit than the other ‘densiflora’ cultivars. It can take very wet soils in winter and very
dry ones in summer.
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| 'Sentinel' manzanita - Theodore Payne Foundation, Sunland CA |
Arctostaphylos
‘Sentinel’, another popular cultivar, is taller (to 8-10 ft with time) and more
upright (4-6 ft wide) than the other A.
densiflora cultivars. It also grows
more quickly than the rest. A natural hybrid (most likely) from the Vine
Hill area, it is more drought and sun tolerant than the other cultivars, though
not as frost hardy. It is often pruned up as a small, multi-trunk ‘tree’ to
exhibit its red-brown bark. This
cultivar has slightly grayer leaves and looks wonderful combined with greener
manzanitas, including ‘Howard McMinn’.
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| Arctostaphylos 'Sentinel' ('Sentinel manzanita) flowers |
‘White
Lanterns’ manzanita is a very dense shrub growing eventually to 5-7 ft
tall by 8-12 ft wide. Similar in
appearance to ‘Howard McMinn’, it has smaller leaves giving it more fine
appearing texture and denser foliage. It
was introduced by the Santa Barbara Botanic Garden from a volunteer seedling
selected by Dara Emery. It makes a
lovely specimen, foundation plant or informal hedge. Like all Vine Hill cultivars, it is
literally covered in white flowers in late winter/early spring.
Arctostaphylos
‘Howard McMinn’ is probably the
best-known and most widely available of the A.
densiflora cultivars. It was
selected by Howard McMinn, botany professor at Mills College, from the college garden
(Oakland), where he raised manzanitas from seed collected at Vine Hill and
other sites. It is speculated to be a hybrid between Arctostaphylos densiflora and perhaps A. stanfordiana.
‘Howard
McMinn’ manzanita was introduced into the nursery trade by the Saratoga
Horticultural Foundation in 1955; it received the ‘Award of Merit’ from the
California Horticultural Society in 1956. So it is relatively old by California native
cultivar standards. There are garden specimens more than 50 years
old - still growing strong! We hope our
plant at Mother Nature’s Backyard will do as well.
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| 'Howard McMinn' manzanita Madrona Marsh native plant garden, Torrance CA |
‘Howard
McMinn’ manzanita is a slow-growing, bushy shrub. It was originally described as a smaller
manzanita, suitable as a groundcover; garden experience has shown it can become
rather large with time, ultimately attaining heights of 6-10 ft and widths of
6-12 feet. But its slow growth will keep
it a medium shrub (4-5 ft tall; 5-6 wide) for many years.
‘Howard McMinn’ has a dense, medium-green
appearance due to its erect leaves (see below).
Gardeners often choose manzanitas
for their evergreen leaves and red-brown bark.
This cultivar displays both from an early age. In fact, from a foliage standpoint, ‘Howard
McMinn’ has to be one of the prettiest manzanitas available.
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| Foliage - 'Howard McMinn' manzanita |
Like
most manzanitas, ‘Howard McMinn’ has a nice natural shape: mounded and dense
when young, more open at the base with age.
Some gardeners like to thin out lower branches to encourage a tree-like
shape. But little pruning is required –
just removing dead branches is all that’s really needed. We like to let manzanitas take their own
shape over time.
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| Flowers and foliage: 'Howard McMinn' manzanita |
Of
course the main attraction this time of year is the flowers. True to its parentage, ‘Howard McMinn’
manzanita puts on quite a show! This
year the flowers were only around for several weeks, probably due to the hot
weather. In a usual year in western Los
Angeles County, this cultivar is covered with flowers for 3-4 weeks from as
early as late January until well into February.
The
flowers are small and urn-shaped – typical for manzanita – and range from pink
to almost white. They are held in rather
dense clusters, mostly on the sunny exterior of the foliage. The
flowers are noticeably smaller than those of our Bigberry manzanita (see: http://mother-natures-backyard.blogspot.com/2014/01/plant-of-month-january-bigberry.html)
making them accessible to European honey bees as well as the longer-tongued
native bees and hummingbirds. On a sunny
day, plants are literally buzzing with pollinators.
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| Flowers - 'Howard McMinn' manzanita |
The
fruits of ‘Howard McMinn’ manzanita are the ‘little apples’ of manzanita
fame. They usually ripen to red-brown in
late spring/early summer in our area.
The fruits are edible and can be made into a refreshing cider-like drink
(more on that this summer). They can be
used to make tasty jellies or syrups; they can also be dried, crushed and used for
a pleasant tea. Of course the
fruit-eating birds like Northern Mockingbirds, Scrub Jays and Cedar Waxwings
will happily devour any left-over fruits.
Birds are also known to nest in mature manzanitas.
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| Manzanita (Arctostaphylos) fruits |
‘Howard McMinn’ is more forgiving than most
manzanitas when it comes to garden conditions.
It can take full sun near the coast, but does better with some afternoon
shade in most local gardens. It loves
well-drained sandy soils, but does fine in clay loams and clays (especially if
planted on a low berm). Quite drought
tolerant once established, ‘Howard McMinn’ is more tolerant than most
manzanitas of a little summer water. But don’t over-water – once a month should be
plenty.
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| Eight year old 'Howard McMinn' manzanita Madrona Marsh native plant garden, Torrance CA |
Use
‘Howard McMinn’ as a specimen shrub in the front or backyard. It’s pretty enough to stand muster in the most
manicured of neighborhoods. It also makes a nice hedge or hedgerow plant. Its size is perfect for hiding a block wall
(as we are doing in Mother Nature’s Backyard). ‘Howard McMinn’ is often used with manzanitas/cultivars that have different
growth or foliage characteristics. The
year-round green contrasts are soothing, and the yearly show of flowers and
fruits is magical. It does well on slopes, making an easy-care slope
cover. Some even advocate it as a
candidate for a large container.
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| Flowering 'Howard McMinn' manzanita on small berm - Madrona Marsh native plant garden, Torrance CA |
However you
use it, Arctostaphylos ‘Howard McMinn’ (and the other Arctostaphylos densiflora cultivars) make great additions to the
garden. They are time proven and should
last a lifetime with proper care.
For more
pictures of this plant see: http://www.slideshare.net/cvadheim/arctostaphylos-densiflora-web-show
For plant
information sheets on other native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html
We
welcome your comments (below). You can
also send your questions to: mothernaturesbackyard10@gmail.com
