Blog: Plums – What to Expect

Plums are a fruit that can be so delicious that you want to keep eating them. At best, they are sweet, succulent, juicy and full of flavour: a delight to eat. However, all too often plums are disappointing, which is a pity. To an extent, this is because retailers try to keep plums on the shelf all year round, but ensuring they are at the best maturity for eating is the biggest issue, while the array of plum types and varieties on sale can be confusing for shoppers.

To get the best of plums throughout the year, it helps to understand the types and varieties, the seasons, how to buy them and how to care for them at home.

Plum Types and Varieties:

There are basically two main types of plums: European plums (Prunus domestica) and Japanese plums (Prunus salicina).

European Plums: These include well-known varieties such as Victoria, Marjorie’s Seedling and Opal, which usually have purple or red coloured skin; soft-textured, juicy, sweet flesh and can be elongated in shape. These are the plums that we most associate with summer: home-grown; delicious; with quite short seasons (August to mid-September); poor for storing, so suddenly arriving in the shops, we enjoy them, then they are gone.

The origin of European plums has been traced to the Caucasian mountains and Caspian Sea region.

Other very seasonal European plum types are sold during the same summer period. These include Greengages, Damsons and Mirabelle plums. Damsons are for jam and gin; greengages are in particular prized for their fabulous honey-sweetness; while the small yellow or red Mirabelle plum, rarely seen in UK supermarkets (occasionally in M&S), is sweet, but mostly used for preserving.

Elizabeth plums are occasionally sold in the winter. This is a marketing name for a number of European plum varieties grown in southern hemisphere countries.

European plums (Prunus domestica) – key varieties:

• Prunus domestica ssp. intermediag. Victoria, Jubileum;
• Greengages (Prunus domestica ssp. italica) e.g. Reine Claude, Cambridge;
• Red Gages (Prunus domestica ssp. italica) e.g. Ferblue, RedOne;
• Damsons (Prunus domestica ssp. insititia) e.g. Shropshire Prune;
• Mirabelle plums (Prunus domestica ssp. syriaca) e.g. Mirabelle de Nancy;
• Elizabeth e.g. D’Agen, Sugar Prune, Van der Merwe.

Japanese Plums: The main plum type on supermarket shelves is the so called Japanese plum. This has a round shape; medium to large size; red, black or yellow skin; yellow or red flesh; and a preference for warm growing conditions. Many varieties can be stored for several weeks, so are well suited to commercial development around the world, hence the dominance of Japanese plums in supermarkets: there is one or other of them on sale throughout the year.

Due to differences in variety, maturity and seasonality, the eating experience of Japanese plums varies hugely from absolutely wonderful to very poor, much more so than European plums.

Japanese plums actually originated in China, but arrived in California, where most modern varieties have been bred, via Japan.

Included within the Japanese plum types are new hybrid varieties, mainly Pluots and Plumcots, that result from crosses between plums and apricots.  Plumegranates and Watermelon plums are other marketing names used to distinguish between various skin appearance and flesh colour combinations of new varieties.

Japanese plums (Prunus salicina) – key varieties:

• Red e.g. African Rose, Sapphire, Purple Majesty, Ruby Sun, Fortune, Laetitia, African Delight, Ruby Star;
• Red with red flesh e. Ruby Red; Ruby Crisp;
• Black e.g. Black Diamond, Black Splendor, Angeleno, Larry Ann;
• Yellow e.g. Sunkiss, Songold, African Pride;
• Pluots (25% apricot and 75 % plum) e.g. Dapple Dandy; Flavorking, Flavorosa, Flavorfall, Rose Sweet;
• Plumcots (50 % apricot and 50% plum) – none in the market at the moment;
• Plum trade mark as Plumegranates e.g. Marco;
• Plum trade mark as Watermelon e.g. Mirelli, Green Red, Metis Safari.

  

Seasons:

Similar to apricots, peaches and nectarines, seasonality has a big influence on eating quality of plums.

Early season varieties are light in texture, flavour and sweetness, though can be delicious. Mid-season varieties generally have the best eating quality, while late varieties, having hung on the trees for longer, can often be quite dense, sometimes crispy, though usually very sweet.

These seasonal differences are most noticeable with the many Japanese plums which stretch over long seasons of production. European plums can also be variable in eating quality, but it is less noticeable due to the short season and storage potential.

Plums by Seasonality – key varieties:

• Early: Sapphire, Purple Majesty, Ruby Sun;
• Mid-season: African Pride Fortune, Flavorking, Black Diamond, Ruby Crisp;
• Late: September Yummy, Laetitia, Songold, African Delight, Ruby Star, Angeleno

  

Maturity:

The timing of harvest has the greatest impact on the final eating experience of plums. For each variety, there is an ideal timing of harvest that allows for transport and sales (up to 6-7 weeks from southern hemisphere countries), while allowing the plum to ripen properly for the customer.

Unfortunately, some importers like to receive harder plums to allow more time for sales, which can reduce potential eating quality.

In theory, because the markets are close-by, Mediterranean plums are harvested when more mature to give better sweetness and flavour. However, this is not always the case: supermarkets have a big influence on this issue, so their focus on the harvest parameters is very important in managing the final eating quality.

Buying Plums:

• Seasons: Be aware of the seasons, so you know what to expect. For example, in April/May and October/November, the main plum variety on sale is Angelino, a late, cheap variety with dense, almost crisp flesh (see chart).
• Punnets: the cheapest plums are in punnets, often at very good prices. These are usually the smallest calibres and unripened. They can be good to eat, but need to left in the fruit bowl to soften. Depending on the retailer, these may be ‘traded’ fruit, so more about price than eating quality, and can be hit-and-miss as to whether they will ripen properly. The more quality-focused supermarkets may ripen the punnet fruit before it goes on sale.
• Ripe and Ready: Most supermarkets offer a ripe and ready pack. These are larger calibre fruit and either better

  

  varieties or batches of fruit with better maturity, and will be more expensive. Beware that ripening is an inexact science, so be prepared to leave the plums in a fruit bowl if they feel a little hard.

• Loose plums: Many supermarkets offer the option of loose plums. These are usually the larger calibres and the most expensive choice, so should be reliably good, though are not necessarily pre-ripened.

At Home:

Early and mid-season Japanese plums need to feel significantly soft to be good to eat. This essentially means putting them in a fruit bowl at room temperature and waiting for them to soften (sometimes for over a week).

It is easy to be impatient and not wait long enough, but look for a darkening of the skin colour and a sense that the softening flesh is extending to the stone. There may even be a little wrinkling of the skin around the stalk cavity, which is normally a sign of eating maturity. The plum may also have a nice aroma indicating that it is ready for eat.

At this stage, the plum should be soft, sweet and juicy with lovely flavour. From any one punnet, there will always be some that ripen faster than others, so check them all each time and take the most mature to eat.

Late varieties of Japanese plums, such as Angelino, are not going to achieve significant softness in the same way. These will keep in a fruit bowl for quite a while, and, as they have hung on the tree for so long, will remain quite firm, with good sweetness.

The same principle applies to European plums, but under-ripeness isn’t such an issue due to the short shelf-life.

Plums can be stored in the fridge, but this will slow ripening considerably.

Plum Quality:

Common problems with plums:

• Plum remains hard and sour: If, after a week in a fruit bowl, the plums are still firm and have not sweetened, they were probably harvested too early and will never ripen properly.
• The plum is tastless with limited sweetness: This may be a problem of the variety, especially those of very early season, though is more often due to the fruit being harvested before properly mature.
• The flesh around the stone is bitter: The fruit is not quite ripe enough for best eating quality.
• Skin wrinkles around the base: A small amount of wrinkling can be a good sign of maturity, but too much wrinkling is a sign of poor handling and storage which may affect the eating quality of the fruit.
• Flesh is lacking in juice or succulence: If the plum seems soft, but the flesh is dry, pappy or juiceless, there has been a problem with age, maturity or long storage.
• Flesh appears to be discoloured and brown: This is often associated with poor juice content and is another sign of maturity and storage problems.
• Flesh appears translucent: Yellow or dappled plums can sometimes seem translucent, which is a sign of advanced ripeness, often still with good eating quality.
• Flesh is crunchy: The plum may be a late season variety which tend to have dense flesh after a long growing season, but may also be a fruit that has been harvested too soon to ripen properly. Late season plums may be dense, but should be sweet.

©Good Fruit Guide 2018. Information and data published on www.goodfruitguide.co.uk must not be reproduced or copied without permission of the editor. Recommendations on fruit varieties and types with the very best taste are personal to the editor of Good Fruit Guide, and do not attempt to be exhaustive or supported by verifiable consumer research.  The highlighting of fruit with the very best taste in the opinion of the editor is not intended as a judgement on the taste of varieties and types of fruit not mentioned.