Differences in "Dactyliferas"

The most important fact that a Landscape Architect must know before specifying Phoenix Dactylifera on a project is that there are many sub-varieties of Phoenix Dactylifera and they don’t all look alike!

Unlike other Phoenix genus palms which are produced solely for ornamental use, Phoenix Dactylifera is farmed for its edible fruit, the date. Over centuries of farming, new and different hybrids have been created (via cross pollination) that then became standardized varieties because the farmer wanted to produce quantities of exactly the same fruit. These farmers discovered that if they wanted to produce an entire grove that yielded a consistent fruit crop, it would be necessary to clone a female palm that was producing the desired fruit. Pollination and subsequent production from seed results in substantial variations in the fruit and is not an effective means of creating a fruit-producing grove. The only reliable method of producing a grove that yields a consistent fruit crop is via the removal & propagation of young shoots. During the first 17 to 20 years of the date palm’s life, it will produce young shoots (also known as suckers) near the base. Many of these will be candidates for mechanical removal and propagation. Some will die but a large number survive and grow to maturity. These shoots, being extremities of the original adult, carry exactly the same characteristics including those of the fruit they produce. As the shoots mature they begin to produce shoots of their own and the process begins again. Eventually, entire groves of palms are created that are all exactly the same sub-variety.

Though many varieties of P. Dactylifera are grown in the United States, only three are available for ornamental applications. They are P. Dactylifera "Deglet Noor", P. Dactylifera "Medjool" and P. Dactylifera "Zahidi". All are Phoenix Dactylifera but each variety is also somewhat unique. The canopies differ in appearance and the palms perform differently when exposed to Florida's wet, disease rich environment.

Medjool

Zahidi

Deglet Noor

P. Dactylifera "Medjool" and P. Dactylifera "Zahidi" are available for ornamental use but are very rare in comparison to P. Dactylifera "Deglet Noor". Combined, "Medjools" and "Zahidis" comprise only 20% of all P. Dactylifera produced in the United States and are characterized by dense silvery green canopies. Similar in many ways, "Medjools" and "Zahidis" have proven themselves to be well suited for ornamental use in many microclimates. We have successfully utilized them on hundreds of job sites in locals ranging from New Orleans, Louisiana all the way to Venezuela. With a modest amount of post installation care these two (2) varieties are excellent performers.

The Deglett Noor is far more readily available then either the Medjool or the Zahidi and it cost’s less to obtain at wholesale. Deglett’s survive transplant very well but we feel that they are not suited for landscape applications in the South. The problem with the Deglett is that it does not produce a dense canopy and it seems to be less tolerant of many of the diseases that are common to the South. When observing Deglett’s out in a southern landscape a common perception is that it is a “weak Medjool”. This happens because the Deglett produces a very thin canopy and tends to lose most of its lower fronds for various reasons once transplanted. Because of these characteristics, the visual impact is almost always negative and so we do not recommend them.

BEWARE

The lower wholesale cost of Deglett’s and the fact that the trunks of all three sub-varieties are similar in appearance has created all manner of confusion and has often resulted in unhappy end users and disillusioned Landscape Architects.

It is an unfortunate fact that many contractors will substitute the Deglett for the more expensive Medjool if they can get it past the owner and LA by leaving the canopies tied during the approval process. Bidding Medjools but installing Deglett’s means a substantial additional profit for the contractor while sacrificing the design and overall look of the completed installation. Because this happens so often (more times then you would want to believe!), I strongly recommend that you implement a painless and non-intrusive method of insuring that your client actually gets the variety and aesthetics you specified. Because visual identification of the sub-variety is nearly impossible with the canopies tied up and because many contractors will tell you that the canopies must remain tied for a period of time or they won’t warrant the palms, identification often becomes a “rock and a hard place” proposition.

In fact, and under these circumstances, it should not be the L.A.’s problem to absolutely ID the sub-variety prior to acceptance; that burden needs to be contractor who is expected to install in accordance with the specs. Even so, many contractors will not themselves know for sure what they are planting (they might not admit this but it is a truth) and so the responsibility must pass to the one party who does know for certain, the contractor’s supplier.

No one knows better then the supplier which sub-variety was delivered to the site. In fact, he is often the only party to the transaction that does know. Requiring that your contractor obtain and submit a notarized certification of variety from his supplier only makes sense and is a requirement that is within normal industry tolerances. Such a certificate must plainly state the Genus, Species and Sub-variety in botanical terms and be both signed and notarized by the supplier of the palms. This simple submittal will insure that if the wrong sub-variety does end up on site, the supplier will be liable to provide the right palms to the landscaper. We all know that many jobs are awarded to a low bidder who may not have the means to buy the correct palms once the money has been spent. This measure insures that he is not stuck and unable to afford to replace the palms should a “mistake” occur.

This requirement is non invasive and protects your design & the end users investment. Groundworks is happy to provide you with blank certificates. You can download one here. All you need to do is instruct that your contractor have his supplier fill it out, sign it and have it notarized. You will thus be assured that you are getting what you specified without going through a difficult and time-consuming acceptance process.