This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Rivers's Early Prolific - This is a most valuable Plurn where it will crop. At Sawbridgeworth, where it was raised, it seems to crop regularly. It is early - coming in at the end of July - and though small is of good quality and readily finds a market where plums will sell at all. On suitable soil, which would seem to be a rich strong loam, it makes a handsome tree (fig. 361).
Fig. 361. - Plums. Early Prolific (Rivers'). Nat. size.
Another Plum raised by the late Mr. Rivers. One of the surest croppers, upright in growth - very susceptible to Aphis attacks. Fruit larger than that of Early Prolific, but of inferior quality, dull red ripening to blackish purple. Season, early August.
A yellow Plum of inferior quality, below medium size, useful for jam and cooking; a heavy cropper. It can often be gathered green the third week in July. It is always a cheap Plum, but as it flowers very late it sometimes misses the frost that has killed those varieties which flowered earlier.
This is called the Worcester Egg Plum. It is inferior in quality to the Gisborne. Is a very heavy cropper and largely used for jam. The fruit is medium-sized, yellow, tinted with gold.
One of Messrs. Rivers's raising, has not been out long enough to get a market character, but has been planted by some growers on the strength of its performances at Sawbridgeworth.
Prince of Wales - This fine-quality Plum is being discarded by many growers because it lias a habit of dying suddenly when apparently in full vigour and without any discoverable reason. Nevertheless it is still useful. It flowers early, and quickly throws a mantle of broad leaves over the young fruitlets. From this cause there is often a better crop of Prince of Wales than of any other Plum; that was the case in Middlesex in 1910. The quality of the fruit is good enough for dessert among ordinary mortals. Fruit roundish oval, bright purple, dotted with yellow.
A large-sized, reddish-purple, strongly-scented plum. A good bearer and producing a large spreading tree requiring plenty of room. Can be gathered for travelling before Victoria.
Everyone knows this bright-red plum, perhaps the most popular grown. It possesses all the characteristics a good plum should possess, except flavour. For the market grower it pays the best of any. The tree is terribly liable to " Silver Leaf". It occasionally bears so profusely as to require thinning of the fruit; if this is done early in July the plums can be sold for green-plum jam or for bottling.
A medium-sized dark plum, perhaps the most delicious cooking plum grown, producing a syrup of peculiarly rich colour. The tree is short-jointed and bushy, like the Damson. A moderate bearer. Season after Victoria.
This handsome scented Plum (fig. 362) with very large oval dark-red fruits is a very shy bearer in Middlesex, but in Kent and Essex it bears a better character. It always finds a ready sale from its attractive appearance. The tree is upright in habit and attains a height of 40 ft. It is very susceptible to "Silver Leaf". Ripe in mid-September.
A fine dark purple plum fit for picking in August and September.
This deep purple-red variety is much grown in places, and may be gathered from mid August. (See coloured plate.)
One of the best of the introductions of Messrs. Rivers. Comes in the latter end of September. The large blackish-purple fruit is round with pointed nose, of great size, with bloom on the skin. The tree is upright-growing, seldom attacked by Aphis, and fairly able to resist the "Silver Leaf" disease (fig. 363).
Fig. 362. - Plums. Pond's Seedling. (2/3).
Fig. 363 - Plum. Monarch (Rivers'). (2/3).
It requires careful consideration before a market grower plants any of the Gage tribe. Except in special localities most of them are woefully shy bearers. The above is one of fair gage flavour, of attractive appearance, and a good cropper in a warm sheltered position. The same may be said of the old and earlier " Greengage " which has deliriously flavoured fruit of a deep yellowish green dotted with crimson.
[w. g. l.]