Is Florence Fennel Invasive? #119

Fennel, Foeniculum vulgare, native to Southern Europe, has long been prized as a kitchen and medicinal herb, but in mild-winter climates like ours it is one of the worst noxious weeds. It readily reseeds, has deep roots from which new plants can regrow, and is quite resistant to many herbicides. It has a PIER (Pacific Island Ecosystem at Risk) score of 19, as compared with scores in the 20s awarded to some of the worst thugs like kudzu vine and cattail, and negative scores given to those that pose no risk. It is a significant problem at many locations in Southern California, including Camp Pendleton, San Elijo Lagoon, and several of the Channel Islands.


Florence fennel, F. vulgare var. azoricum, is a cultivar that produces an edible bulb-like leaf base. It was developed in Italy, probably in the 17th century, but has only been popular in this country from the 1980s. Given the problems posed by its wild cousin, two questions arise:  Does Florence fennel share the aggressiveness of wild fennel, and can Florence fennel revert to a plant resembling the wild form if it is allowed to propagate unsupervised?


Given the right conditions, when allowed to form seed heads, Florence fennel can spread in the garden. Its deep roots make it a bit of a chore to dig up. The plants produce an unidentified 'allelopathic' chemical that inhibits the growth of other species in their vicinity. If seeds of Florence fennel were to find their way to a sensitive environment, I have no doubt that they could displace threatened native plants. However, with wild fennel already widespread in California, I doubt there is much risk that home gardeners will exacerbate the problem.


I've found nothing on the Internet reporting that the bulbing fennel will revert to the wild. We have replanted from saved seed, but for no more than two or three generations, with no apparent deterioration in quality. Might the first sign of reversion be an increased frequency of 'male' plants? Or is it 'female' plants? When I last wrote on this subject, twelve years ago, there were still people posting on the Internet that fennel was dioecious, that is, that the male and female sexual parts were to be found on separate plants. In fact, all plants are hermaphrodite, and the supposed sexual dimorphism was based on the occurrence of rounder bulbs, considered more desirable at the table, and a flatter type that became more frequent late in the season. There is a difference of opinion about whether the fat bulbs are male or female, and those who write about it cite authorities such as their Sicilian grandmothers. It's likely that it depends on from where in Italy your ancestors hailed. I prefer to attribute masculinity to the skinny ones.


The bulbing leaf bases of Florence fennel are the result of selective breeding and, no doubt, if the plants were left to themselves the enlarged base, that confers no survival advantage and imposes a cost on the organism, would disappear after a few dozen generations. Saving seeds for a season or two seems not to be a problem. If you want to encourage good bulbing, you should start the seed early in the season, September or October; avoid crowding when you set them out, separating the plants by at least five inches; and keep them well watered. You should harvest them as soon as the bulbs approach the size of a tennis ball, because they tend to become bitter if they are left in the ground. New plants will grow from the roots after the bulbs are cut but, in my experience, they will all be 'male.'

Posted on May 11, 2022 .

Lobelia #118

Lobelia is a large genus, including over 400 species, with nearly a worldwide distribution. You wouldn't guess from the appearance of the flowers that it belongs to the bellflower family (Campanulaceae). The most familiar species, L. erinus, native to southern Africa, is the source of the edging and basket cultivars with attractive blue flowers and names like 'Crystal Palace' and 'Cambridge Blue,' but there are also white and red varieties. It is established as somewhat of a weed in our garden. We pull it out where it's not wanted and let it grow if it self-seeds in the right spot. Other species we have grown include the Mexican lobelia (L. laxiflora), and the eastern North American L. cardinalis. Neither is considered seriously invasive, but they can get aggressive when pampered. Another North American species, L. inflata or Indian tobacco, is the main source of the alkaloid, lobeline.

Most species are poisonous, producing lobeline and other related and unrelated pharmacologically active compounds. L. inflata has a long history of use in Native American medicine for a variety of therapeutic and ceremonial indications, but its most obvious effect was as an emetic, giving it another popular name, puke weed. In folk medicine it was smoked as a treatment for asthma and was used for this condition by mainstream physicians through the 19th and early 20th centuries. In more recent times its main use was as an aid to smoking cessation.

Quit-smoking aids containing lobeline were sold with trade names like Nikoban and Bantron in the form of tablets, lozenges, and chewing gum through most of the 20th century. In 1993 the FDA banned the sale of over-the-counter smoking deterrents on the grounds that research showed that they were ineffective. The timing is significant because in the next year Congress made its huge gift to the snake oil industry with the Dietary Supplement Health and Education Act of 1994. The effect of the legislation was that substances that fell within the very broad definition of "dietary supplements" could be sold over the counter with no requirement that they demonstrate either safety or efficacy.

Lobeline acts on the nervous system in a complex manner, but the mechanism that has stimulated most interest is its ability to modify the release of the neurotransmitter, dopamine, in response to nicotine and other addicting substances such as methamphetamine and ethanol. Dopamine plays a major part in "reward-motivated behaviour," or, in popular terms, it is "the chemical of pleasure."

Surprisingly, given that there is good basic science evidence that lobeline could be useful as a treatment for tabagism and several other addictions, there has been little effort on the part of the industry to reintroduce OTC lobeline products. Amazon will sell you "NicRx natural anti smoking pills with lobelia" but lobelia is listed last among ten herbal ingredients. I could find no mention of lobelia in a 2003 publication listing the components of the 100 most commonly prescribed herbal medications in Germany, where a prescription is required for many botanicals sold over the counter in this country. There have been few attempts at a clinical trial of lobeline for smoking cessation, and the most recent Cochrane review, dated 2012, found no studies that met their criteria for inclusion in a meta-analysis.

Posted on February 28, 2022 .

Fava 'Robin Hood' #117

When I was in medical school we learned about favism as a cause of haemolytic anaemia in Mediterranean countries. It was only when I went to England in 1960 that I learned that favas,  broad beans, were an item of diet in the Anglosphere. We didn't commence eating them until we grew our own a dozen years later. Even now we find that many friends think that 'broad beans' are the same as lima beans. Favas are rarely if ever to be seen in the supermarket and, even in ethnic markets, I suspect you would only find them dried. This is strange because fresh favas are a wonderful gourmet treat, and they are easily grown in the home garden.

'Broad Windsor' is the most readily available variety, but over the years we've tried others such as 'Medes' and 'The Sutton' from Thompson & Morgan, which ceased selling in the USA a few years ago. They offered somewhat smaller plants with a slightly more delicate flavour. We generally make two plantings, one in September or early October and one in January. The beans reach harvest size in late February or early March, and the second planting extends the harvest by a few weeks. Flowers don't appear until the plants reach about three feet in height and don't set fruit until they reach four or five feet. We pinch off the tops when they reach six feet and that seems to encourage fruiting, though it may be more because the weather is favourable by that time. The plants languish as the temperature rises in late May.

Favas are not much troubled by pests and diseases, but you need to be concerned about two enemies. The black bean aphid (Aphis fabae) can be devastating if you let it get out of hand. It first appears on the growing tips of the plants, and if they are pinched off, given a spritz of insecticidal soap or acephate, or even sprayed with a jet of water, the pest won't spread. We've only had serious damage in one of the nearly 50 years we have grown favas. More of a problem is chocolate spot disease, caused by the fungus, Botrytis fabae. There was one season when it ruined our harvest when I made the dual mistakes of planting saved seeds in a bed where we had recently grown favas. Seed can be successfully saved but you should discard any that show evidence of damage by the fungus.

In the last few years, we have grown 'Robin Hood,' a variety developed in England a dozen years ago. It is a small plant, growing to 12 to 18 inches according to the catalogues. In our hands some of the plants will reach three feet or more and should be given support. The flowers set fruit close to the ground and hold the blossoms from mid-January. The result is a very productive plant and a long harvest season. The photo will give you an idea of how productive they are with many harvest-sized pods crowded at the base of the plant and plenty of new blossoms setting more fruit higher up.

The beans are green rather than pearl grey when they first reach harvest size, and they can grow larger before they need "double shelling."  Most of the recipes for fresh favas that you see online recommend that you remove the seed coat. When the beans are young there is no need for this and they impart a slight, but very pleasant, bitterness to the taste which is lost when they are removed.

Posted on January 31, 2022 .

Disease Resistant Peas #116

You rarely see English peas in their pods at the supermarket. Frozen peas aren't bad, and the bags are quite useful for icing sprains and bruises, but fresh peas are one of the great treats reserved for the home gardener.

When we began growing our own peas, we planted 'Tall Telephone,' which I still believe is unmatched for flavour. A March planting produced wonderfully in June but, by the second year, the vines were so attacked by mildew that we turned to other varieties. For a while we grew 'Green Arrow' and then 'Mr Big.' By the 1990s the problems with disease were so bad that we gave up on English peas and turned to snap peas, which were somewhat more tolerant. Ten years ago, I wrote enthusiastically in this column about the English pea, 'Legacy,' which showed good resistance to disease and amazing productivity, but it also failed after a year or so. Mildew was unsightly but didn't prevent the plants from producing some useful pods. The real problem was Fusarium wilt whose symptoms are disheartening. The plants germinate and appear to flourish until around the time the first flowers appear. Then, over a few days, the vines turn brown, beginning at soil level, and the plant soon dies or produces only a few undersized pods. The culprit is Fusarium oxysporum f. sp. pisi, which is subclassified into several races, notably races 1 and 2. I believe that our main problem is race 2, given the symptoms and the varieties that have proven susceptible. I think our past partial success with varieties like 'Legacy,' 'Bolero,' and the snap pea, 'Cascadia,' can be attributed to their resistance to race 1, and our subsequent failure to their susceptibility to race 2. It persists in the soil for years, so crop rotation is not likely to be effective in a small home victory garden.

Most of the seed catalogues don't tell you anything about whether their varieties are disease-resistant, or they describe them as resistant without specifying which of the many plant ailments they tolerate. If you want information about resistance, you're more likely to find it at sites catering to commercial growers.

This year we were more successful with 'PLS 560,' though some of the plants withered during the warm weather of May and June. We are growing it again with no evidence of disease, but that may be in part because we planted in a bed where we have not grown peas before. We are growing 'Bolero' successfully in the same bed. I have read that Fusarium requires soil temperatures above 70° to flourish, and we have certainly had more trouble with wilting in April to June.

This is the first time we have grown a pea that is resistant to both race 1 and race 2. 'PLS 560' is an 'afila' variety whose vines have many tendrils and only a few leaves. They are favoured by growers because the tendrils intertwine so that the vines support each other, saving labour costs. I'd also give PLS 560 high marks for flavour. You can get it from Territorial Seeds.

The only other hybrid resistant to both races of Fusarium wilt that I can find in quantities suitable for the home gardener is PLS 566, sold by Harris Seeds. I haven't tried it yet but plan to do so.

Posted on January 4, 2022 .

Bare Root Strawberries #115

For more than 50 years one of our most important November garden tasks was to plant strawberries. The local nurseries always had inexpensive and healthy bare root plants of varieties suitable for our zone 24 climate. We first grew 'Lassen,' then switched to 'Sequoia,' and finally settled on 'Seascape' as the best to provide quality fruit over a long season. Seascape will bear as early as March, but the fruit is sour and flavourless until May, and so we pinch off the blossoms until early April. Twenty to 25 plants will give us all the fruit we can use through May, June and most of July. After being dissatisfied with the results of growing plants from runners over a second season, we plant new bare root plants every year.

Over the last decade we have become increasingly disappointed with the bare root plants we found in the local nurseries. They were appearing later in the season, fewer varieties were available, and the quality of the plants worsened. Four years ago we had only a handful of survivors after buying three lots of plants, and we gave up on trying to buy them locally. Buying online also was a challenge. It seems that the big box suppliers weren't interested in catering to the small southern California market and insisted that the planting time in our zone is February or March, a time when we could be picking ripe berries if we wanted to let them mature that early. And so, with some trepidation, I turned to Amazon. There wasn't a lot of choice when I first tried that source in December 2019, but I was able to order 25 plants from Hand Picked Nursery. They came, looking much healthier than anything I had seen locally for several years, and included a few extra plants. Twenty-five survived and throve through the following summer. In 2020 I ordered both 'Seascape' and 'Mara des Bois' from the same source with similar results. This year I put in my order as soon as they appeared on the Amazon website and planted them November 1st. The plants were obviously in better condition when I ordered them earlier and, ten days later, 27 of 28 plants are flourishing. This company, located in North Carolina, also supplies 'Chandler' and 'Camarosa,' two other varieties recommended for southern California.

Last summer we picked an overabundance of 'Seascape' from early May through most of July and useful quantities through most of August. The 'Mara des Bois' were good until mid-June, but after that the berries were sparse and small. Only a few had the wonderful fragrance that so excited garden writers when they first became available in this country. In spite of having reported favourably after my first two seasons of growing them, I don't think I'll be planting them again. I realize that others, including Chino's, grow them successfully, but I think I have enough experience with them to say that other varieties will be more satisfactory close to the ocean.

Posted on December 1, 2021 .

Starting Legumes from Seed #114

The seeds of beans and peas can be sown directly in the ground, but that method exposes them to several hazards. They can rot before they germinate, especially during the cool weather which is best for garden peas and favas. The infant sprouts can be devoured by soil pests like sowbugs before they reach daylight,  which is one of the causes of what I call pollywogs, beans that emerge showing only cotyledons and failing to develop true leaves. Finally, the survivors may be poorly spaced, crowded in part of the row and with gaps elsewhere.

In the past we have reduced these problems by sprouting the seeds between layers of damp paper towels, setting them out when the rootlets reach about a quarter inch in length. That doesn't completely deal with the soil pests but leaves them exposed to attack for a shorter time before they emerge.

This year that strategy also failed us. I suspect that the seed companies, for reasons related to the pandemic, are selling older and less viable seed, increasing our losses because of low germination and less vigorous young plants. I am now starting seed in 2-1/2 inch round pots, though 6-packs might work almost as well. For some varieties whose germination may be 40% or less, I plant two or three seeds per pot. Even if all three seeds germinate, they are easily separated for planting at this young stage with almost complete survival after setting out. This method is a bit more work, but it's so successful that I'll stick with it, even if seed quality improves in the future, which I suspect it won't.

Because of the deteriorating quality of seed, the losses from sprouting to mature plant, and the stingy quantities sometimes provided by the seedsmen, we have turned more and more to saving seeds from our own plants. This strategy won't work for hybrids, but most legume seeds are open-pollinated. The flowers are self-fertile and cross-pollination between varieties doesn't occur readily, though the authorities recommend separating them by 10 to 20 feet. That makes it possible to start 40 to 50 seeds with each planting, which would seem a lot to supply one elderly couple, but sometimes it's barely enough. If we do find the harvest excessive, we have plenty of friends and family, so it doesn't go to waste.

The legume seeds we've saved geminate reliably for at least two years when kept indoors at room temperature. If we wanted to keep them longer, we would freeze them in airtight containers, such as plastic prescription bottles, with a packet of silica desiccant. Seeds need to be thoroughly dried before they are put in an airtight environment. Otherwise, they are likely to mildew. I find that just leaving them exposed to the air in a cool but not dark place works fine. Keeping them in a dark closet is a bad idea if you live close to the beach, as we do. Mildew will surely find them.

Posted on November 5, 2021 .

Sweet Corn #113

Eleven years have gone by since I last wrote about corn and it's time for an update. Many of our friends are surprised at our success in growing corn in foggy La Jolla, since one has a mental picture of tall stalks waving in the breeze under a scorching midwestern sun. In fact, it's one of our most reliable summer crops, keeping us well supplied from late May until mid-November. The heirloom varieties of corn that you remember from childhood, like Golden Bantam, have a rich flavour and are very sweet when first picked. Conversion of sugar to starch begins immediately after harvest and proceeds rapidly over a few hours. That was the source of the old maxim, "be sure that the water is boiling before you cut the ear". Over the years the breeders have enhanced the sweetness and have increased the holding ability of their varieties by developing the 'se' trait, which both increases the sugar content and inhibits the conversion of starch to sugar. A further improvement was made with the Super Sweet shrunken 2 (sh2) gene resulting in even more sweetness and very delayed starch formation. The result is that the corn you buy from the supermarket has quite an acceptable quality and we can cut all of the ears from a planting when they are at the ideal stage of maturity with very little deterioration when we keep them in the refrigerator for a week or more.

We have grown several varieties over the years, beginning with Illini X-tra Sweet and Ruby Queen. Fifteen years ago, we switched to the bicolour, 274A, which allegedly combined the extra sweetness conferred by the 'sh2' trait with the tenderness of the 'se' types. It lived up to the claims and we stuck with that variety until four years ago. Then, intrigued by the glowing description in the Stokes catalogue, we tried the yellow variety, 'Elle'. It was definitely superior to 274A, both for eating quality and for vigorous growth. As I wrote earlier this year, Stokes will no longer provide US customers with quantities of seed suitable for the home gardener and so we turned to the developer, Harris Seeds. I couldn't buy fewer than 1000 seeds but was able to share some of the abundance with friends and family.

'Elle' belongs to a group of varieties dubbed "Quality Elite" by Harris and described in their literature as "the best tasting, highest quality sweet corn available on the market today." We would agree with their claim and have received enthusiastic confirmation from several friends. For those of you who worry about such things, I should add that 'Elle' is not a GMO product. Harris does have a line of seeds called "Biotech Sweet Corn" but they are available only to registered growers who have signed a stewardship agreement.

After nearly half a century of growing corn, we have our technique down to a science. With the goal of getting nine to a dozen plants, I put three seeds per cell into a 6-pack. These are ready to set out when the seedlings are about six inches in height. The roots may be tangled but the young plants don't seem to be bothered much, even if they have to be torn apart. I plant them about eight inches apart in three or four rows to assist wind-pollination. After a couple of days I sprinkle about an ounce of granular balanced fertilizer around each plant and water it in thoroughly. I make six or seven plantings per season, the first early in March and the last in mid-August.

Since I have ben spraying the silks with spinosad, the European corn borer has not been a problem. We did have some damage on the first planting this year and I realized that the two-year old spinosad had lost its kick. We've had no further trouble after I bought a new bottle. Aphids can be very numerous on the husks of the mature cobs, but they don't seem to affect the quality of the edible portion. We have had significant problems with the corn blotch leaf miner, though it is described as "an occasional pest that feeds within corn leaves but does not usually result in potential yield loss". I'll leave further discussion to a future article.

 

Posted on October 1, 2021 .

Padron Pepper #112

After half a century of growing our own produce, we have become almost independent of the supermarket. We have achieved this by learning when to plant various vegetables for a year-round harvest, and also by adjusting our diet to what is in season. We have been assisted by the changing climate which has greatly lengthened the harvest season for some frost-tender crops like tomatoes, cucumbers and eggplants. The penalty we have paid for so intensively cultivating our beds is that the soil is loaded with pathogens ,and for many vegetables we can grow only the most disease-resistant varieties, having had to give up on many desirable heirlooms.

We have not found a sweet pepper sufficiently resistant to thrive in our garden. With luck we may get two or three undersized fruit from a bell pepper plant and so we perforce turn to the supermarket when we need them. Happily, chili peppers aren't bothered by our soil diseases, and we grow several types. However, most of them are much too hot for our northern palates and the crop goes to Juan, the gardener, and his friends. This year we grew the famous Padrón pepper and it was a great success, flourishing in our garden and providing an amount of spiciness that we can both tolerate and enjoy.

These peppers were first cultivated from seeds brought from the New World to the Franciscan monastery at Herbón, near the town of Padrón in Galicia. In Europe 'pemento de Herbón' is recognized as a protected designation of origin but the seed is widely available online. We planted them in containers in early February, keeping them in a sunny widow until they were ready to set out in early May. The fruit began to reach harvest size, about two inches long, early in July and the three plants have churned out more than we can use for the last month. If you pick the fruit when it is small, under three inches, most of them are only slightly spicy, but you will occasionally get a fiery one ("Some are hot, and some are not.") The pungency increases as they mature and is augmented if the plants are stressed by underwatering. They will eventually turn red but they are normally eaten young and green. They are a favourite item in tapas, heated in a skillet with olive oil until the skin is blistered. You will find scores of recipes for their preparation on the Internet, all much the same. They can be added to many other dishes that benefit from a bit of zing. Helen even put some in a batch of zucchini bread.

Unfortunately, they don't seem as impervious to soil-borne fungi as some of the scorchers now established as perennial in our garden. I'll plan on a second planting in future years, a strategy we have found essential for even the most disease-resistant tomatoes.

Posted on September 1, 2021 .