The Pātea and Districts First World War memorial, consisting of four plaques on memorial gates to the Pātea Domain, was unveiled in 1922 [1]. After the Second World War a new district memorial was erected in the site fronted by these two Phoenix palms. The initial plaques were transferred there, and the new memorial was unveiled on 7 November 1954 [2]. From a photo dated circa 1960, where the two palms are about 1 metre high, a planting date of about 1956 seems likely. The planting was possibly due to the actions of the Pātea Beautifying Society which was active at the time (Wattrus, personal communication). The use of Phoenix palms in Pātea is another example of the association between war memorials and the palms, additionally showing the aesthetic utility of planting a pair or more, rather than solitary specimens (for example, see war memorials at Papakura, Akaroa [3], Awapuni Racecourse [4] and the Old Levin Cemetery Soldiers’ Section [5]. The palms also have a popular culture presence due to their visibility in the YouTube for the 1984 New Zealand number one hit Poi E (about half-way through the video, in the scenes in front of the Aotea Waka Memorial) [6].
Acknowledgment: Thanks to Bronwyn Wattrus, Aotea Utanganui - Museum of South Taranaki, for information and permission to use the archival photo.

References:
1. Patea War Memorial Ministry for Culture and Heritage, accessed 26.08.2023.
2. Bronwyn Wattrus, Aotea Utanganui - Museum of South Taranaki (Note: the building seen in the circa 1960 photo was demolished in 1981).
3. See record CR/G1625
4. See record MWR/G1904
5. See record MWR/G1905
6. 1984 New Zealand number one hit Poi E See full video on YouTube