QBARS - v14n2 Variation in Temperature Due to Location

Variations in Temperature Due to Location
by Josephine Polivka, Portland, Oregon

Our home is located in Portland Heights, that is, the north slope of the west hills of Portland south of Burnside street. The coast and geodetic survey informs us that our altitude is approximately 594 feet above sea level. Our land about here is a steep slope, dropping 24 feet every 400 feet.
Our house faces southwest, more west than south. On the northeast side of our house we have nothing but camellias and azaleas, and this area is in partial shade. During the summer months, these plants receive the early morning sun, but no sun at all in fall and winter.
Directly above, or south of us, is Ascension Chapel, one of those hideous "Gothic" little churches built by our earnest but ignorant ancestors in the 1880s. It has an extraordinarily high peaked roof and steep slopes. Consequently air drainage is not down our lot, but to the sides. The sanctuary end of the chapel, in fact, sits 6 inches on our lot. We have a raised bed here, about 3 feet high. A parish hall is extended from the little chapel, and this provides a wind shelter from west and south winds. The lots to the east of us are higher than ours, and we are fairly sheltered from the east wind, but entirely exposed to the northeast wind.
Our 50 by 100 lot is level. Air drainage is very good-there are no frost pockets. In front of our house are planted all our rhododendrons, which, consequently all have full sun in the summer months, plus early sun in the spring, and no sun at all, except at the extreme southwestern corner, in the winter months.
Our soil is a light yellow greasy clay, impenetrable in winter, and so hard in summer that it has to be worked with a pick axe. It defies the ordinary shovel. Not feeling we could afford to have the whole lot dug up and new top soil put on, we planted most of the garden to heather. We have found the heather is a fighting plant, only surpassed by violets. When we dig up a heather, we always find that the soil is crumbly and friable, though it doesn't seem to do anything for humus.
The Gerke Landscapers designed our little garden with great skill and we started out equipped with nothing but a real love of plants and profound ignorance. The first thing we did was to over plant. Our first visit to the Test Gardens at Crystal Springs was a deep shock - we saw our dwarfs as they would some day be. Beginning last fall we started transplanting our dwarfs and every spring and fall for some time, that will be the No. 1 chore!
We have had a disastrous infestation of symphyllids which killed two R. 'Moonstone', and one R. 'Bow Bells', 6 heathers, and 10 Gaultheria miqueliana . The county agent kindly sent a young man out who discovered the pest and advised us to dig up the whole garden, spade in Aldrin, and replant We did not, however, dig up the heathers, all of whom are well established plants which resent being moved, and usually die when we try it.
However, on the portions of the garden that we did dig up, we seemed to have success, except that the one R. 'Moonstone' we left in the ground because it looked so healthy, died this summer. Again the county agent sent a man who said to sprinkle Aldrin on the top of the ground and water it in. He warned us that this was dangerous, and sure enough, it killed every shallow rooted ground cover we had left! However, it did not affect the Hellebores , the Kalmia latifolia , Skimmia , or any rhododendron. The men from the county agent tell us that control by commercial growers is comparatively easy, but that no one has worked out a satisfactory operation for the average home gardener where fumigation is not practicable.
Now to the thermometer and its readings. It is a recording type located at the front, or southwest corner of the house. We have found that the temperature readings are always two degrees higher than the outdoor thermometer we have on the northeast side of the house. This varies only when the air is absolutely still, which is very rare here. When there is no wind at all, the temperature is the same back and front.
Rhododendrons that we have growing here in our garden are:

R. 'Idealist'	R. williamsianum
R. lutescens	R. pemakoense
R. 'Bow Bells'	R. 'Carmen'
R. hemitrichotum	R. haematodes
R. forrestii var. repens	R. 'Moonstone'
R. leucaspis	R. 'Elizabeth'
R. keleticum	R. 'Purple Splendor'

Along the fence between our property and the chapel property, we have planted a row of rhododendrons, in loving memory of a clergyman who died suddenly a few years ago, and a man we both loved very dearly. In obtaining the consent of the chapel to plant on their ground, we undertook to water and mulch, etc., all these rhododendrons.
This row contains: R. 'Arthur J. Ivens', R. 'Conemaugh', R. 'Tessa', R. 'Rose Elf', R. 'Carmen', R. 'Jock', R. 'Blue Tit', R. 'Moonstone' and R. 'Cilpinense'. It is 60 feet long (the row) and not so over planted as it sounds!
We must gain a good deal of protection from the hills, the big old houses, and the big old trees here than we realized. We have about three to every five frosts as compared to the airport area. I wonder if the few degrees of difference between our house and the airport plains might mean the difference between life and death to cold tender plants.
I should imagine that any rhododendron grower who lives on the south slope of our west hills would report weather conditions considerably different from us, and also from the two official Portland temperature stations. I always thought it must be much warmer on the south slope, but whenever I investigate my opinions I usually find them to be wrong!