Friday, February 1, 2013

Citrus - the sequel

About a year ago, I blogged on citrus, enthusing about the ornamental citrus that are not only part of the landscape throughout this region, but also produce some very pleasant fruit for those that take the trouble to pick them. Just this week, we relinquished the keys to our old property and so I took the opportunity to stock up on grapefruit and lemons to last us until I return to the UK.

Grapefruit - fresh from the tree - so unlike the sharp ones in the UK!

You will also have read in my last blog, that I had purchased three new citrus trees to be planted in our new garden. Before I did this I took the opportunity to do a little research and fill the gaping gap in my knowledge. Despite having been  a horticulturalist for well over 40 years, I have never had the opportunity to grow citrus before and so really knew little about cultivars or how to grow them.

As always, it's amazing what you can find on the internet and I soon located an excellent small book, simply entitled 'Citrus', written by Lance Walheim. As well as touching on the history of citrus and techniques for planting and growing, it lists over 100 cultivars of citrus, indicating whether they are suitable for California, Arizona, Texas or Florida. And in our case it distinguishes between different areas including deserts of California which is where we live. Here the climate is characterised by long hot summers which are ideal for many types of citrus. Fruit ripens early, much of which is at its peak during the winter and the flesh is sweet.

Although originating from tropical and semitropical climates, citrus trees will actually tolerate quite low temperatures and even some frost, which we do sometimes get here.  Young foliage, flowers or immature fruit may be damaged but mature fruit, which is more likely to be present in winter, can withstand more cold as it has higher sugar levels.

Tangelos - sweet but very pippy!

Coming from the UK, I am very familiar with growing apples and pears and the need for the correct pollinator in order for the fruit to set and a crop to be produced. I admit I had no idea with regard to citrus trees. Most are self compatible, which means that they can utilise their own pollen and there is no need for a different cultivar to act as a pollinator. Some types of citrus are even simpler and whether or not they get pollinated,  just go ahead and produce fruit regardless by a process called parthenocarpy. (You might also be interested to know that aphids produce young without mating and the process goes by the same name resulting in the rapid increase of greenfly and blackfly - today's useless fact!) Getting back to citrus, some cultivars, such as satsumas produce sterile pollen which results in seedless fruit, although if there are other cultivars in the neighbourhood, cross pollination may occur resulting in the odd seed in otherwise seedless fruit.

Citrus blossom - very sweetly perfumed

Comparing again with apples and pears, I questioned as to whether the trees were grafted and whether there were different root stocks and indeed there are. Trees are available on dwarfing rootstocks that will reduce the size of the mature tree considerably. Rootstocks may also control disease resistance, hardiness, cropping and be particularly suitable for certain soils. Sometimes fruiting citrus are grafted onto a curious little ornamental called Poncirus trifoliata, which is almost hardy in the UK. I remember learning its name years ago as a student as it was growing outside the dining hall at Writtle college where we queued three times a day for college fodder! However the average citrus tree bought in most ordinary garden centres does not have the rootstock identified, so it's a bit of a gamble.

Poncirus trifoliata

The Citrus section at Mollers Garden centre - nice trees but rather expensive at $79 each

Having done my homework, last week I purchased my three new citrus trees. The lemon is an 'Improved Meyer' which is said to be a hybrid between a true Lemon and the mandarin orange resulting in a unique flavour which is both lemony and fairly high in sugar. We chose 'Rio Red' for our grapefruit which is a red fleshed fruit, said to have a good flavour and be juicy. We had wanted a seedless satsuma but these are one group of fruits which do not grow well in the heat of the desert and so we opted for a mandarin orange and found a cultivar called 'Fairchild' that is recommended for this area.

 'Improved Meyer Lemon'
I love the skin tints on these red fleshed grapefruit

Mandarin 'Fairchild'

All I need to do now is plant them and wait five years!


  1. Hopefully, the time flies until they are fruit-bearing, and between the UK and Palm Springs. Maybe, you'll own that house by then, and those are your trees, too?

    Citrus - the grapefruits must be amazing in that summer heat.

  2. Fresh, properly ripened grapefruit are wonderful!

  3. We know very little about Citrus as well, as garden plants anyway but for eating a fair bit! A nice and concise introduction to citrus there, they at least do make a nice patio plant in the summer here and perhaps we'll eventually grow one if ever we have a conservatory in the future.