Brexit shines a bright light on that fact by forcing us to consider the trading relationship we have with Europe.
At the same time, a heightened awareness of biosecurity threats does the same. Those threats are directly proportional to the volumes of high-risk host plants imported.
It would be naive to think that UK production will increase dramatically overnight, but it does seem likely that UK dependence on European stock will decline over time. If we believe that will happen, what does the road that takes us from here to there look like?
The HTA has carried out fact-finding research on oaks, chosen because a high biosecurity risk status means oak import data is available. Nurserymen now know how many oaks are imported each year.
Detail is as yet incomplete. We do not yet know the sizes of imported plants but UK nurseries must surely be thinking of increasing production to satisfy that demand.
Right now the trade is rightly concerned about Xylella, for which lavender is a high-risk host plant. It is refreshing to hear UK nurserymen discussingthe fact that we have traditionally bought such large volumes of this crop from southern Europe and asking how we might replace that production here in the UK.
We do not have the sunshine of Spain, but that no longer holds back UK production of tomatoes. UK growers also recognise the fact that continental producers deliver efficiencies by producing this crop in very large volumes — a small number of producers do the job for the whole trade.
I guess the final piece in the solution will be recognition of the "value" of high-quality UK production. Will the customer recognise a "biosecurity premium"?
Ultimately production increases because producers have confidence that they will sell increased production and that confidence traditionally comes about as a result of discussions between producers and their customers. Right now the euro exchange rate makes European stock expensive and we are likely to see the smarter UK buyers doing what they can to mop up limited UK production before their colleagues.
If that situation continues, and experts anticipate that it will, smart plant buyers will be thinking about not only securing current UK production but also taking action to see that increase over time.
Tim Edwards is chairman of Boningale Nurseries