Growing Roses in Olympia
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Growing roses in
the Olympia area presents challenges beyond those found in most
other parts of the country. No, we don't have Japanese
beetle here, nor oak root fungus, but we are Blackspot Kings.
Western Washington's climate is described as having four
seasons: rain, more rain, still raining, and road work.
Winter here is cool and wet; spring is cool and damp and slow to
warm up; summer is warm, dry, and all-too-short; fall is cool
and damp again. The sun shines for about 65% of summer
days, but only 30% of winter days. Olympia is in
USDA Hardiness zone 7b,
which means average winter lows of about 10°F, although 20°F is
more typical; and
AHS Heat Zone 4, which means only 15-30 days a year over 86°F.
Some years we don't even get as many as 15 hot days. We
Sunset zones 4 and 5. Roses
might freeze in winter, but equally likely they won't; however
summers don't offer enough heat to produce a lot of blooms.
2 to 3 bloom cycles is the best you can expect here. But,
the blooms we do get are huge and long-lasting!
According to the
Western Regional Climate Center, Olympia's average maximum
temperatures range from 44°F in January to 77°F in July and
August. Average minimum temperatures range from 31°F in
January to 49°F in July and August. Freezing temperatures
are common December through March, but rarely low enough to
damage roses severely. Our growing season runs from
120-150 days, with about 150-200 frost-free days. Last
frost in spring is generally considered to be past on Mother's
Day, which is when all of Olympia rushes out to buy hanging
fuchsia baskets for Mom. First frost in fall is usually
around early October, but may be as late as December. Frost, however, is not damaging to
roses. Damaging temperatures, usually those below about
20°F, occur sporadically, mainly from late November to early
March. Pipe-bursting freezes have occurred as early as
Halloween, however. Every few years we get what we
call an Alberta Clipper: intensely dry and cold weather, carried
on a northeast wind, from the general direction of Alberta.
Alberta Clippers can produce single digit temps, or even
subzero. Roses (and pipes) will freeze in these conditions. And
pretty much every winter brings a
windstorm that can damage
roses, either by dropping a fence, power pole, or tree into the
rose garden, or by partially uprooting the roses themselves.
Our gravelly sandy soils don't give rose roots much mechanical
traction, especially when waterlogged, as they often are during
these windstorms (mid-latitude cyclones). Roses growing in
gravelly soils can be just about yanked right out of the ground in high
While our total
annual precipitation is no greater than that for the eastern
half of the country, it tends to fall as a 9-month-long
continuous drizzle, rather than distinct showers and downpours
separated by days and weeks of sun. This presents some
problems for roses. Blackspot, for one; spot anthracnose
for another; and botrytis rot for another. Roses that are
disease-resistant in other areas, aren't here. Disease
pressure is very high - our climate is very favorable to fungi
such as blackspot, anthracnose and botrytis. Growing roses
will require some attention to protection from fungal pathogens.
On the flip side, mites are rarely troublesome here - they do
not like our climate at all!
falls in every month, though very little falls in July or
August. The rainy season generally runs from October
through April. Annual precipitation averages anywhere from
50-60". Roses will need to be watered while actively
growing, from May into September, as average precipitation
during that period is significantly less than the 1" per week
needed by the roses.
Some snow falls
every year, usually in January or February, but snow is on the
ground for less than 5 days per year on average. Snow here
tends to be heavy and wet and can damage climbing roses, tree
roses, and the larger shrub roses. Snow can form effective
insulation in some parts of the country, but not here. Not
enough of it falls, it doesn't stick around more than a few
days, and the coldest weather is clear and dry, not snowy.
(But, as this website was being developed, Olympia was buried
under 1-3ft of snow for 10 days, preceded by single-digit
temperatures, and followed by every single river in Western
Washington jumping its banks as all that snow melted under 11" of
rain and 50
soils are young soils - the glaciers only just retreated about
12,000 years ago after all. Nearly half of the populated
area of the county is on glacial upland soils, so most soils in our area are
high in sand and gravel, and low in clay and organic matter, which
together mean that the soil has little ability to hold either
water or nutrients. The
USDA's soil surveys describe
Olympia-area soils as being well-drained and leached of
nutrients. Water drains through fast, and fertilizer
doesn't last long. Pockets of clay loams appear here and
there, which will retain water and nutrients and can be very
good gardening soils. Alluvial soils and glacial outwash
soils are excellent gardening soils - fine sand loams and silt
loams. Much of the rest of the area is glacial gravelly
till - like gardening in dirty aquarium gravel. Most gardens will benefit
from addition of compost and other organic materials to the soil
on a regular basis. Fast-acting fertilizers disappear
fast; organic fertilizers will last much longer.
Encapsulated slow-release fertilizers, however, need warm soil
to work, and we don't get that here until July or August.
The high rainfall
means that the soil here is generally acidic, as low as pH
of 4 or so on some sites, although gardens are usually about pH
5.5 - 6.5. This plays havoc with nutrient
availability! Most gardeners add lime in fall, although it
won't be necessary every year except in the extremely acidic
soils. And, our river valley soils can be neutral, or even
a little alkaline, so don't make assumptions.