QBARS - v9n2 Golden Gate Park Progress

Golden Gate Park Progress
by Roy L. Hudson, San Francisco, California

It is time to write another chapter in the development of the John McLaren Memorial Rhododendron Dell in Golden Gate Park, San Francisco, California.
Much progress has been made as well as a few errors and the reason for successor failures should be of equal interest to sincere students of the genus. Efforts to correct mistakes often teach us more than a planting which, due to ideal conditions for a given variety, gives little or no trouble. The truth is only too apparent. All rhododendrons are not for all people. Reluctantly we are forced to agree with many who have tried before us that the R. griersonianum hybrids are not going to live up to their rating in the San Francisco Bay area. We refused to accept the judgment passed on them and worked up a large stock of many varieties. These were placed in every conceivable location and condition that we could provide. The results have been far from satisfactory. The severe burning of the foliage is apparent no matter what we do with them and makes them very unattractive most of the year. Heavy bloom combined with insufficient leaf surface to support the plant, results in a high mortality rate. They also bloom so late that in this mild climate new growth is well advanced and tends to obscure the flowers and spoil the mass effect. They are poor competition indeed for such glorious beauties as R. 'Mrs. G. W. Leak', R. 'Mrs. Furnival' or R. 'Gills Crimson'.
R. 'Pink Pearl', 'White Pearl', 'Cynthia' and 'Fastuosum Flore-plenum' are still the backbone of the large park plantings where their vigor and size are desirable characteristics. R. 'Cornubia' and the selected clone R. 'John McLaren' are extremely valuable and dependable and here again their size and comparative legginess is an asset that is not appreciated in a tiny home garden. They lead off the season with us and are just going over now. (March twelfth) A worthy companion in this early installment of beauty is the old R. arboreum hybrid, 'Pink Delight'. The handsome foliage, so like arboreum, is a perfect foil for the freely borne, large trusses of two toned, pink flowers. Frost or rain seem to do little damage to the flowers and our group of plants are fully exposed to sun and wind.
The outstanding varieties in our collection and the most satisfactory from the standpoint of ease of culture, freedom of bloom and year around beauty of foliage and habit, are the Dutch hybrids. R. 'Earl of Athlone', R. 'Langley Park', R. 'The Hon. Jean Marie de Montague', R. 'Unknown Warrior', R. 'Van Nes Sensation' and R. 'Prof. Hugo De Vries' are only a few of the completely satisfactory varieties.
The many forms of Loderi are doing well and have reached a size and age to be heavily budded for the coming season. Last spring a plant of R. 'Loderi Venus' produced a floral display that surpassed anything I have been privileged to see in this or any other family of plants.

One cultural essential for 'Loderi' was learned the hard way. Drafts or ground winds must be protected against. The constant whipping of the heavy leaves causes the flow of nutrients through the petiole to be impaired or interrupted and results in loss of health and eventual death of the entire plant. We lost several plants before planting a low but tight, informal hedge of Viburnum odoratissimum . Improvement was immediate and now the plants are in vigorous good health. R. 'Naomi' responded to the same treatment and all of the various named clones look extremely promising.
We excel in the Maddenii series and it may seem incredible to distant readers that we have a bed of nuttallii (Fig. 17) in a fully exposed position on a south slope in full sun buffeted by the prevailing westerlies. The plants are far more compact and attractive than those grown in the shade and they are beginning to bud up rather well. I had the extreme honor and pleasure of showing these plants to our esteemed President, Mr. C. I. Sersanous this very day and I am sure he will substantiate the above.

Rhododendron burmanicum , of the same series, of which I have already written in glowing terms, Oct. 1953 Bulletin A.R.S. is living up to the billing but a few modifications of the earlier descriptions are in order. As the plants have grown older they have settled into a more definite blooming period and show very little of the pre-season color which was so unusual for the first few years. The branches tend to shed a good many leaves as they elongate and the plants have a slightly sparse look than they previously did. The bud set is still nearly one hundred per-cent in spite of a heavy seed set of last year which has never been removed. The base branching has decreased but can easily be encouraged by heavy pruning. Local breeders are trying many crosses with this species and some interesting varieties may be expected in the near future.

In general, throughout the garden, settling of the plants is the chief source of trouble. Rhododendrons simply cannot stand being too deep. The literature is wise to constantly repeat this warning so that beginners will not make the common mistake of planting too deep or allowing the plants to settle and become covered over with soil. Experience with thousands of plants tends to prove this causes the death of many more rhododendrons than all other causes combined.
This year, for the first time, due to a shortage of our favorite mulch, pine needles, we have used hundreds of yards of mill shavings. However, they were not used inside of the drip line of the plants. We mulched heavily around the plants with pine needles and then covered all the intervening space with a six inch layer of shavings. In addition to conserving moisture we hope to reduce our weed growth in this way as it is becoming a very serious maintenance problem as we extend the plantings over a wide area.